PLANNING AND DESIGNING A RESEARCH STUDY
Engaging in research can be an exciting and rewarding endeavor. Through research, scientists attempt to answer age-old questions, acquire new knowledge, describe how things work, and ultimately improve the way we all live. Despite the exciting and rewarding nature of research, deciding to conduct a research study can be intimidating for both inexperienced and experienced researchers alike. Novice researchers are frequently surprised—and often overwhelmed—by the sheer number of decisions that need to be made in the context of a research study. Depending on the scope and complexity of the research study being considered, there are typically dozens of research related issues that need to be addressed in the planning stage alone. As a result, the early stages of planning a research study can often seem overwhelming for novice researchers with little experience (and even for seasoned researchers with considerable experience, although they may not always freely admit it).
As will become clear throughout this chapter, much of the work involved in conducting a research study actually takes place prior to conducting the study itself. All too often, novice researchers underestimate the amount of preparatory groundwork that needs to be accomplished prior to collecting any data. Although the preliminary work of getting a research study started differs depending on the type of research being conducted, there are some research-related issues that are common to most types of research. For example, prior to collecting any data at all, researchers must typically identify a topic area of interest, conduct a literature review, formulate a researchable question, articulate hypotheses, determine who or what will be studied, identify the independent and dependent variables that will be examined in the study, and choose an appropriate research methodology. And these are just a few of the more common research-related issues encountered by researchers. Furthermore, depending on the context in which the research is taking place, there may be a push to get the research study started sooner rather than later, which may further contribute to the researcher’s feeling overwhelmed during the planning stage of a research study.
In addition to these research-related issues, researchers may also need to consider several logistical and administrative issues. Administrative and logistical issues include things such as who is paying for the research, whether research staff need to be hired, where and when the research study will be conducted, and what approvals need to be obtained (and from whom) to conduct the research study. And this is just a small sampling of the preliminary issues that researchers need to address during the planning stage of a research study.
The purpose of this chapter is to introduce you to this planning stage.
Because research studies differ greatly, both in terms of scope and content, this chapter cannot possibly address all of the issues that need to be considered when planning and designing a research study. Instead, this chapter will focus on the research-related issues that are most commonly encountered by researchers in all scientific fields (particularly those that involve human participants) when planning and designing a research study. In some ways, you can think of this chapter as a checklist of the major research-related issues that need to be considered during the planning stage. Although some of the topics discussed in this chapter may not be applicable in the context of your particular research, it is important for you to be aware of these issues. After discussing how researchers typically select the topics that they study, this chapter will discuss literature reviews, the formulation of research problems, the development of testable hypotheses, the identification and operationalization of independent and dependent variables, and the selection and assignment of research participants. Finally, this chapter will conclude with a discussion of the impact of multicultural issues on research.
Choosing a Research Topic
The first step in designing any research study is deciding what to study.
Researchers choose the topics that they study in a variety of ways, and their
decisions are necessarily influenced by several factors. For example, choosing a research topic will obviously be largely influenced by the scientific field within which the researcher works. As you know, “science” is a broad term that encompasses numerous specialized and diverse areas of study, such as biology, physics, psychology, anthropology, medicine, and economics, just to name a few. Researchers achieve competence in their particular fields of study through a combination of training and experience, and it typically takes many years to develop an area of expertise. As you can probably imagine, it would be quite difficult for a researcher in one scientific field to undertake a research study involving a topic in an entirely different scientific field. For example, it is highly unlikely that a botanist would choose to study quantum physics or macroeconomics. In addition to his or her lacking the training and experience necessary for studying quantum physics or macroeconomics, it is probably reasonable to conclude that the botanist does not have an interest in conducting research studies in those areas. So, assuming that researchers have the proper training and experience to conduct research studies in their respective fields, let’s turn our attention to how researchers choose the topics
that they study (see Christensen, 2001; Kazdin, 1992).
Interest
First and foremost, researchers typically choose research topics that are of interest to them. Although this may seem like common sense, it is important to occasionally remind ourselves that researchers engage in research presumably because they have a genuine interest in the topics that they study. A good question to ask at this point is how research interests develop in the first place. There are several answers to this question.
Many researchers entered their chosen fields of study with longstanding
interests in those particular fields. For example, a psychologist may have decided to become a researcher because of a long-standing interest in how childhood psychopathology develops or how anxiety disorders can be effectively treated with psychotropic medications. For other researchers, they may have entered their chosen fields of study with specific interests, and then perhaps refined those interests over the course of their careers. Further, as many researchers will attest, it is certainly not uncommon for researchers to develop new interests throughout their careers. Through the process of conducting research, as well as the long hours that are spent reviewing other people’s research, researchers can often stumble onto new and often unanticipated research ideas.
Regardless of whether researchers enter their chosen fields with specific
interests or develop new interests as they go along, many researchers become interested in particular research ideas simply by observing the world around them (as discussed in Chapter 1). Merely taking an interest in a specific observed phenomenon is the impetus for a great amount of research in all fields of study. In summary, a researcher’s basic curiosity about an observed phenomenon typically provides sufficient motivation for choosing a research topic.
Problem Solving
Some research ideas may also stem from a researcher’s motivation to solve
a particular problem. In both our private and professional lives, we have probably all come across some situation or thing that has caught our attention as being in need of change or improvement. For example, a great deal of research is currently being conducted to make work environments less stressful, diets healthier, and automobiles safer. In each of these research studies, researchers are attempting to solve some specific problem, such as work-related stress, obesity, or dangerous automobiles. This type of problem solving research is often conducted in corporate and professional settings, primarily because the results of these types of research studies typically have the added benefit of possessing practical utility. For example, finding ways for employers to reduce the work-related stress of employees could potentially result in increased levels of employee productivity and satisfaction, which in turn could result in increased economic growth for the organization. These types of benefits are likely to be of great interest to most corporations and businesses.
Previous Research
Researchers also choose research topics based on the results of prior research, whether conducted by them or by someone else. Researchers will
likely attest that previously conducted research is a rich and plentiful source of research ideas. Through exposure to the results of research studies, which are typically published in peer-reviewed journals for a discussion of publishing the results of research studies), a researcher may develop a research interest in a particular area. For example, a sociologist who primarily studies the socialization of adolescents may take an interest in studying the related phenomenon of adolescent gang behavior after being exposed to research studies on that topic. In these instances, researchers may attempt to replicate the results obtained by the other researchers or perhaps extend the findings of the previous research to different populations or settings. As noted by Kazdin (1992), a large portion of research stems from researchers’ efforts to build upon, expand, or reexplain the results of previously conducted research studies. In fact, it is often quipped that “research begets research,” primarily because research tends to raise more questions than it answers, and those newly raised questions often become the focus of future research studies.
Theory
Finally, theories often serve as a good source for research ideas. Theories can serve several purposes, but in the research context, they typically function as a rich source of hypotheses that can be examined empirically. This brings us to an important point that should not be glossed over—specifically, that research ideas (and the hypotheses and research designs that follow from those ideas) should be based on some theory (Serlin,1987). For example, a researcher may have a theory regarding the development of depression among elderly males. In this example, the researcher may theorize that elderly males become depressed due to their reduced ability to engage in enjoyable physical activities. This hypothetical theory, like most other theories, makes a prediction. In this instance, the theory makes a specific prediction about what causes depression among elderly males. The predictions suggested by theories can often be transformed into testable hypotheses that can then be examined empirically in the context of a research study.
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Theory
A theory is a conceptualization, or description, of a phenomenon that
attempts to integrate all that we know about the phenomenon into a concise statement or question.
In the preceding paragraphs, we have only briefly touched upon several
possible sources for research ideas. There are obviously many more sources we could have discussed, but space limitations preclude us from entering into a full discourse on this topic. The important point to remember from this discussion is that research ideas can—and do—come from a variety of different sources, many of which we commonly encounter in our daily lives.
Throughout this discussion, you may have noticed that we have not commented on the quality of the research idea. Instead, we have limited our discussion thus far to how researchers choose research ideas, and not to whether those ideas are good ideas. There are many situations, however, in which the quality of the research idea is of paramount importance. For example, when submitting a research proposal as part of a grant application,
the quality of the research idea is an important consideration in the funding decision. Although judging whether a research idea is good may appear to be somewhat subjective, there are some generally accepted criteria that can help in this determination. Is the research idea creative? Will the results of the research study make a valuable and significant contribution to the literature or practice in a particular field? Does the research study address a question that is considered important in the field? Questions like these can often be answered by looking through the existing literature to see how the particular research study fits into the bigger picture. So, let’s turn our attention to the logical next step in the planning phase of a research study: the literature review.
Review of Literature
The phrase ‘review of literature’ consists of two words: Review and Literature. The word ‘literature’ has conveyed different meaning from the traditional meaning. It is used with reference to the languages e.g. Hindi literature, English literature, Sanskrit literature. It includes a subject content: prose, poetry, dramas, novels, stories etc. Here in research methodology the term literature refers to the knowledge of a particular area of investigation of any discipline which includes theoretical, practical and its research studies.
The term ‘review’ means to organize the knowledge of the specific area of research to evolve an edifice of knowledge to show that his study would be an addition to this field. The task of review of literature is highly creative and tedious because researcher has to synthesize the available knowledge of the field in a unique way to provide the rationale for his study.
The very words ‘review’ and ‘literature’ have quite different meanings in the historical approach. In historical research, the researcher does much more than review already published material, he seeks to discover and to integrate new information which has never been reported and never considered. The concept and process implied in the term ‘review of literature’ have such different meanings in historical as compared with survey and experimental research.
The term ‘review of literature’ has been defined in the following ways:
According to Good, Barr and Scates “The competent physician must keep abreast of the latest discoveries in the field of medicine. Obviously the careful student of education, the research worker and investigator should become familiar with location and use of sources of educational information.”
According to W.R. Borg
“The literature in any field forms the foundation upon which all future work will be built. If we fail to build the foundation of knowledge provided by the review of literature our work is likely to be shallow and naive and will often duplicate work that has already been done better by some one else.”
According to Charter V. Good
“The keys to the vast storehouse of published literature may open doors to sources of significant problems and explanatory hypotheses and provide helpful orientation for definition of the problem, background for selection of procedure, and comparative data for interpretation of results. In order to be creative and original, one must read extensively and critically as a stimulus to thinking.”
According to John W. Best
“Practically all human knowledge can be found in books and libraries. Unlike other animals that must start a new with each generation, man builds upon the accumulated and recorded knowledge of the past. His constant adding to the vast store of knowledge makes possible progress in all areas of human endeavour.”
In survey and experimental research, the review of the literature serves a variety of background functions preparatory to the actual collection of data. In these research approaches, the literature is reviewed to create the context from the past for the new study to be conducted with new subjects and newly gathered data. In the historical approach, we never ignore the past and, in the sense review of the literature is the method of data collection if ‘literature’ is used in the broadest possible sense. In this regard the sources used are the ‘subjects’ of the research and the material reviewed of the ‘data’. Therefore, the primary function of the review of literature in the historical research is to provide the research data.
Reviewing the literature has two phases. The first phase includes identifying all the relevant published material in the problem area and reading that part of it with which we are not thoroughly familiar. We develop the foundation of ideas and results on which our own study will be built. The second phase of the review of literature involves writing this foundation of ideas into a section of the research report. This section is for the joint benefit of the researchers and readers. For the researcher, it establishes the background in the field. For the readers it provides a summary of the thinking and research necessary for them to understand the study.
Need of Literature Review
The review of literature is essential due to the following reasons:
1. One of the early steps in planning a research work is to review research done previously in the particular area of interest and relevant area quantitative and qualitative analysis of this research usually gives the worker an indication of the direction.
2. It is very essential for every investigator to be up-to-date in his information about the literature, related to his own problem already done by others. It is considered the most important prerequisite to actual planning and conducting the study.
3. It avoids the replication of the study of findings to take an advantage from similar or related literature as regards, to methodology, techniques of data collection, procedure adopted and conclusions drawn. He can justify his own endeavour in the field.
4. It provides as source of problem of study, an analogy may be drawn for identifying and selecting his own problem of research. The researcher formulates his hypothesis on the basis of review of literature. It also provides the rationale for the study. The results and findings of the study can also be discussed at length.
The review of literature indicates the clear picture of the problem to be solved. The scholarship in the field can be developed by reviewing the literature of the field.
Objectives of Review of Literature
The review of literature serves the following purposes in conducting research work:
1. It provides theories, ideas, explanations or hypothesis which may prove useful in the formulation of a new problem.
2. It indicates whether the evidence already available solves the problem adequately without requiring further investigation. It avoids the replication.
3. It provides the sources for hypothesis. The researcher can formulate research hypothesis on the basis of available studies.
4. It suggests method, procedure, sources of data and statistical techniques appropriate to the solution of the problem.
5. It locates comparative data and findings useful in the interpretation and discussion of results. The conclusions drawn in the related studies may be significantly compared and may be used as the subject for the findings of the study.
6. It helps in developing experts and general scholarship of the investigator in the area investigated.
7. It contributes towards the accurate knowledge of the evidence or literature in one’s area of activity is a good avenue towards making oneself. This knowledge is an asset ever afterwards, whether one is employed in an institution of higher learning or a research organization.
Bruce W. Tuckman (1978) has enumerated the following purposes of the review:
1. Discovering important variable.
2. Distinguishing what has been done from what needs to be done.
3. Synthesizing the available studies to have perspective.
4. Determining meanings, relevance of the study and relationship with the study and its deviation from the available studies.
Edward L. Vockell (1983) has pointed out the following two purposes:
a. The main purpose of this review is to put the hypothesis to be examined in the research report into its proper context.
b. Secondary purposes of this part of the report are to provide readers with guidelines regarding where they can look to find more information and to establish the author’s credential by letting readers know that the researcher is aware of what has been going on with regard to the current and related topics.
The review of literature provides some insight regarding strong points and limitations of the previous studies. It enables him to improve his own investigation.
Principles and Procedures for the Review of Literature
The following is the specific procedure through which review can be done appropriately:
1. It is generally advisable to get first and over all view by consulting a general source, such as a text-book which is more likely to provide the meaning and nature of the concepts and variables or theoretical framework of the field. The logical starting point is to get a clear picture of the problem to be solved. A text-book usually provides the theoretical aspects of the problem. It is very essential to develop deep understanding about the variables and the field.
2. After developing the insight about the general nature of his problem, the investigator should review the empirical researches of the area. The best reference for this phase is the handbook of research. Encyclopedia of Educational Research, the Review of Educational Research and International Abstracts for more upto-date findings. The researcher’s major concern at this point should be to get a clear picture of the field as a whole; specific details are important at this stage. He should start from a topical outline and a temperature set of classifications, so that whatever he reads can be made meaningful.
3. The research for library material must be systematic and thorough. The investigator generally should start by collecting his references from the educational index. When a large number of references are to be copied, they should be typed because precision is required here.
4. The researcher should take note systematically in the light of such criteria as uniformity, accuracy and ease of assembly. The notes should be taken on the card. Each entry should be made separately; references should be recorded with complete bibliographic data. It should be recorded on front side of the card and content should be taken below and reverse side of it. Each note should be recorded carefully and accurately.
5. The investigator should take as complete notes as he might need. On the other hand, taking unnecessary notes is wasteful. The useful and necessary material should be recorded precisely. It would be better that similar sources are gathered. It is necessary that a general education of each source, rather than simply a summary of its content be made. Such evaluation is necessary both in presenting the study in the review of literature, and in using the study as background for the interpretation of the findings of the study.
6. A major pre-requisite for effective library work is the ability to read at high speed. This can only be developed through practice. He must learn to skim material to see what it has to contribute to the study, only after its reference has been established, it should be read in detail. Surveying the literature for the purpose of conducting research is not just ‘a pleasant excursion in the wonderful word of books’, it is a precise and exacting task of locating specific information for the specific purpose.
7. The actual note-taking process is always a difficult task for the researcher. He has to spend long hours in the library taking notes by hand. It is a very tedious job and leads to importance to carelessness and illegibility. He should make use of the facilities available in the library for this purpose
Reviewing the literature has two phases. The first phase involves identifying all the relevant published material in the problem area and reading that part of it with which we are not thoroughly familiar. As we read what others have done and/or thought about the problem area, we gradually develop the foundation of ideas and results on which our own study will be built. The second phase of the review of the literature Involves writing this foundation of ideas into a section of the research report.
Once a researcher has chosen a specific topic, the next step in the planning phase of a research study is reviewing the existing literature in that topic area. If you are not yet familiar with the process of conducting a literature review, it simply means becoming familiar with the existing literature (e.g., books, journal articles) on a particular topic. Obviously, the amount of available literature can differ significantly depending on the topic area being studied, and it can certainly be a time-consuming, arduous, and difficult process if there has been a great deal of research conducted in a particular area. Ask any researcher (or research assistant) about conducting literature reviews and you will likely encounter similar comments about the length of time that is spent looking for literature on a particular topic.
Fortunately, the development of comprehensive electronic databases has facilitated the process of conducting literature reviews. In the past few years, individual electronic databases have been developed for several specific fields of study. For example, medical researchers can access existing medical literature through Medline; social scientists can use PsychINFO or PsychLIT; and legal researchers can use Westlaw or Lexis. Access to most of these electronic database services is restricted to individuals with subscriptions or to those who are affiliated with university-based library systems. Although gaining access to these services can be expensive, the advent of these electronic databases has made the process of conducting thorough literature reviews much easier and more efficient. No longer are researchers (or their student assistants!) forced to look through shelf after shelf of dusty scientific
journals. The importance and value of a well-conducted and thorough literature review cannot be overstated in the context of planning a research study (see Christensen, 2001). The primary purpose of a literature review is to help researchers become familiar with the work that has already been conducted in their selected topic areas. For example, if a researcher decides to investigate the onset of diabetes among the elderly, it would be important for him or her to have an understanding of the current state of the knowledge in that area.
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PsychINFO
PsychINFO is an electronic bibliographic database that provides abstracts and citations to the scholarly literature in the behavioral sciences and mental health. Psych-INFO includes references to journal articles, books, dissertations, and university and government reports. The database contains more than 1.9 million references dating from 1840 to the present, and is updated weekly
Literature reviews are absolutely indispensable when planning a research study because they can help guide the researcher in an appropriate direction by answering several questions related to the topic area. Have other researchers done any work in this topic area? What do the results of their studies suggest? Did previous researchers encounter any unforeseen
methodological difficulties of which future researchers should be aware when planning or conducting studies? Does more research need to be conducted on this topic, and if so, in what specific areas? A thorough literature review should answer these and related questions, thereby helping to set the stage for the research being planned.
Often, the results of a well-conducted literature review will reveal that the study being planned has, in fact, already been conducted. This would obviously be important to know during the planning phase of a study, and it would certainly be beneficial to be aware of this fact sooner rather than later. Other times, researchers may change the focus or methodology of their studies based on the types of studies that have already been conducted. Literature reviews can often be intimidating for novice researchers, but like most other things relating to research, they become easier as you gain experience.
Formulating a Research Problem
After selecting a specific research topic and conducting a thorough literature review, you are ready to take the next step in planning a research study: clearly articulating the research problem. The research problem typically takes the form of a concise question regarding the relationship between two or more variables. Examples of research problems include the following: (1) Is the onset of depression among elderly males related to the development of physical limitations? (2) What effect does a sudden dip in the Dow Jones Industrial Average have on the economy of small businesses? (3) Will a high-fiber, low-fat diet be effective in reducing cholesterol levels among middle-aged females? (4) Can a memory enhancement class improve the memory functioning of patients with progressive dementia?
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Criteria for
Research Problems
Good research problems must meet three criteria (see Kerlinger,1973). First, the research problem should describe the relationship between two or more variables. Second, the research problem should take the form of a question. Third, the research problem must be capable of being tested empirically (i.e., with data derived from direct observation and experimentation)
When articulating a research question, it is critically important to make sure that the question is specific enough to avoid confusion and to indicate clearly what is being studied. In other words, the research problem should be composed of a precisely stated research question that clearly identifies the variables being studied. A vague research question often results in methodological confusion, because the research question does not clearly indicate what or who is being studied. The following are some examples of vague and nonspecific research questions: (1) What effect does weather have on memory? (2) Does exercise improve physical and mental health? (3) Does taking street drugs result in criminal behavior? As you can see, each of these questions is rather vague, and it is impossible to determine exactly what is being studied. For example, in the first question, what type of weather is being studied, and memory for what? In the second question, is the researcher studying all types of exercise, and the effects of exercise on the physical and mental health of all people or a specific subgroup of people? Finally, in the third question, which street drugs are being studied, and what specific types of criminal behavior?
An effective way to avoid confusion in formulating research questions is by using operational definitions. Through the use of operational definitions, researchers can specifically and clearly identify what (or who) is being studied (see Kazdin, 1992). Researchers use operational definitions to define key concepts and terms in the specific contexts of their research studies. The benefit of using operational definitions is that they help to ensure that everyone is talking about the same phenomenon. Among other things, this will greatly assist future researchers who attempt to replicate a given study’s results. Obviously, if researchers cannot determine what or whom is being studied, they will certainly not be able to replicate the study. Let’s look at an example of how operational definitions can be effectively used when formulating a research question.
Let’s say that a researcher is interested in studying the effects of large
class sizes on the academic performance of gifted children in high population
schools. The research question may be phrased in the following manner: “What effects do large class sizes have on the academic performance of gifted children in high-population schools?” This may seem to be a fairly straightforward research question, but upon closer examination, it should become evident that there are several important terms and concepts that need to be defined. For example, what constitutes a “large class”; what does “academic performance” refer to; which kids are considered “gifted”; and what is meant by “high-population schools”?
To reduce confusion, the terms and concepts included in the research question need to be clarified through the use of operational definitions. For example, “large classes” may be defined as classes with 30 or more students; “academic performance” may be limited to scores received on standardized achievement tests; “gifted” children may include only those children who are in advanced classes; and “high-population schools” may be defined as schools with more than 1,000 students. Without operationally defining these key terms and concepts, it would be difficult to determine what exactly is being studied. Further, the specificity of the operational definitions will allow future researchers to replicate the research study.
Articulating Hypotheses
The next step in planning a research study is articulating the hypotheses that will be tested. This is yet another step in the planning phase of a research study that can be somewhat intimidating for inexperienced researchers. Articulating hypotheses is truly one of the most important steps in the research planning process, because poorly articulated hypotheses can ruin what may have been an otherwise good study. The following discussion regarding hypotheses can get rather complicated, so we will attempt to keep the discussion relatively short and to the point.
As briefly discussed in Chapter 1, hypotheses attempt to explain, predict, and explore the phenomenon of interest. In many types of studies, this means that hypotheses attempt to explain, predict, and explore the relationship between two or more variables (Kazdin, 1992; see Christensen, 2001). To this end, hypotheses can be thought of as the researcher’s educated guess about how the study will turn out. As such, the hypotheses articulated in a particular study should logically stem from the research problem being investigated.
Before we discuss specific types of hypotheses, there are two important points that you should keep in mind. First, all hypotheses must be falsifiable. That is, hypotheses must be capable of being refuted based on the results of the study (Christensen, 2001). This point cannot be emphasized enough. Put simply, if a researcher’s hypothesis cannot be refuted, then the researcher is not conducting a scientific investigation. Articulating hypotheses that are not falsifiable is one sure way to ruin what could have otherwise been a well- conducted and important research study. Second, a hypothesis must make a prediction (usually about the relationship between two or more variables). The predictions embodied in hypotheses are subsequently tested empirically by gathering and analyzing data, and the hypotheses can then be either supported or refuted.
Now that you have been introduced to the topic of hypotheses, we
should turn our attention to specific types of hypotheses. There are two
broad categories of hypotheses with which you should be familiar.
Null Hypotheses and Alternate Hypotheses
The first category of research hypotheses includes the null hypothesis and the alternate (or experimental) hypothesis. In research studies involving two groups of participants (e.g., experimental group vs. control group), the null hypothesis always predicts that there will be no differences between the groups being studied (Kazdin, 1992). If, however, a particular research study does not involve groups of study participants, but instead involves only an examination of selected variables, the null hypothesis predicts that there will be no relationship between the variables being studied. By contrast, the alternate hypothesis always predicts that there will be a difference between the groups being studied (or a relationship between the variables being studied).
Let’s look at an example to clarify the distinction between null hypotheses and alternate hypotheses. In a research study investigating the effects of a newly developed medication on blood pressure levels, the null
hypothesis would predict that there will be no difference in terms of blood pressure levels between the group that receives the medication (i.e., the experimental group) and the group that does not receive the medication (i.e., the control group). By contrast, the alternate hypothesis would predict that there will be a difference between the two groups with respect to blood pressure levels. So, for example, the alternate hypothesis may predict that the group that receives the new medication will experience a greater reduction in blood pressure levels than the group that does not receive the new medication.
It is not uncommon for research studies to include several null and alternate hypotheses. The number of null and alternate hypotheses included
in a particular research study depends on the scope and complexity of the study and the specific questions being asked by the researcher. It is important to keep in mind that the number of hypotheses being tested has implications for the number of research participants that will be needed to conduct the study. This last point rests on rather complex statistical concepts that we will not discuss in this section. For our purposes, it is sufficient to remember that as the number of hypotheses increases, the number of required participants also typically increases.
In scientific research, keep in mind that it is the null hypothesis that is tested, and then the null hypothesis is either confirmed or refuted (sometimes phrased as rejected or not rejected). Remember, if the null hypothesis is rejected (and that decision is based on the results of statistical analyses, which will be discussed in later chapters), the researcher can reasonably conclude that there is a difference between the groups being studied (or a relationship between the variables being studied). Rejecting the null hypothesis allows a researcher to not reject the alternate hypothesis, and not rejecting a hypothesis is the most we can do in scientific research. To be clear, we can never accept a hypothesis; we can only fail to reject a hypothesis . Accordingly, researchers typically seek to reject the null hypothesis, which empirically demonstrates that the groups being studied differ on the variables being examined in the study. This last point may seem counterintuitive, but it is an extremely important concept that you should keep in mind.
Directional Hypotheses and Nondirectional Hypotheses
The second category of research hypotheses includes directional hypotheses and nondirectional hypotheses. In research studies involving groups of study participants, the decision regarding whether to use a directional or a nondirectional hypothesis is based on whether the researcher has some idea about how the groups being studied will differ. Specifically, researchers use nondirectional hypotheses when they believe that the groups will differ, but they do not have a belief regarding how the groups will differ (i.e., in which direction they will differ). By contrast, researchers use directional hypotheses when they believe that the groups being studied will differ, and they have a belief regarding how the groups will differ (i.e., in a particular direction). A simple example should help clarify the important distinction between directional and nondirectional hypotheses. Let’s say that a researcher is using a standard two-group design (i.e., one experimental group and one control group) to investigate the effects of a memory enhancement class on college students’ memories. At the beginning of the study, all of the study participants are randomly assigned to one of the two groups. Subsequently,
one group (i.e., the experimental group) will be exposed to the memory enhancement class and the other group (i.e., the control group) will not be exposed to the memory enhancement class. Afterward, all of the participants in both groups will be administered a memory test. Based on this research design, any observed differences between the two groups on the memory test can reasonably be attributed to the effects of the memory enhancement class.
In this example, the researcher has several options in terms of hypotheses. On the one hand, the researcher may simply hypothesize that there will be a difference between the two groups on the memory test. This would be an example of a nondirectional hypothesis, because the researcher is hypothesizing that the two groups will differ, but the researcher is not specifying how the two groups will differ. Alternatively, the researcher could hypothesize that the participants who are exposed to the memory enhancement class will perform better on the memory test than the participants who are not exposed to the memory enhancement class. This would be an example of a directional hypothesis, because the researcher is hypothesizing that the two groups will differ and specifying how the two groups will differ (i.e., one group will perform better than the other group on the memory test). See Rapid Reference 2.5 for a tip on how to distinguish between directional and nondirectional hypotheses.
Choosing Variables to Study
We are now very close to beginning the actual study, but there are still a few
things remaining to do before we begin collecting data. Before proceeding
any further, it would probably be helpful for us to take a moment and see where we are in this process of planning a research study. So far, we have discussed how researchers (1) come up with researchable ideas; (2) conduct thorough literature reviews to see what has been done in their topic areas (and, if necessary, to refine the focus of their studies based on the results
of the prior research); (3) formulate concise research problems with clearly defined concepts and terms (using operational definitions); and (4) articulate falsifiable hypotheses. We have certainly accomplished quite a bit, but there is still a little more to do before beginning the study itself.
The next step in planning a research study is identifying what variables
will be the focus of the study. There are many categories of variables that can appear in research studies. However, rather than discussing every conceivable one, we will focus our attention on the most commonly used categories. Although not every research study will include all of these variables, it is important that you are aware of the differences among the categories and when each type of variable may be used.
