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Basic Process/Concept in
UNIT 1 BASIC PROCESS/CONCEPT IN Research
RESEARCH
Structure
1.0 Introduction
1.1 Objectives
1.2 Definition and Meaning of Research
1.3 Criteria of Good Research
1.4 Objectives of Good Research
1.5 Qualities of a Good Research
1.6 Research Process: Basic Considerations
1.6.1 Context of Discovery 1.6.1.1 Role of Theories, Hypotheses and Paradigms in Psychological Research 1.6.1.2 Research Biases 1.6.2 Context of Justification 1.6.2.1 Scientific Attitudes and Values Associated with Research Process 1.6.2.2 Objectivity Safeguard in Research Process
1.7 Steps in Research Process
1.7.1 Step-I: Identification of the Problem 1.7.2 Step-II: Formulating a Hypothesis 1.7.3 Step-III: Identifying, Manipulating and Controlling Variables 1.7.4 Step-IV: Formulating a Research Design 1.7.4.1 Constructing Device for Observation and Measurement 1.7.4.2 Sample Selection and Data Collection 1.7.5 Step-V: Data Analysis and their Interpretation 1.7.6 Step-VI: Drawing Conclusion 1.7.7 Step-VII: Preparation of Report and Publication
1.8 Importance of Research in Psychology
1.9 Let Us Sum Up
1.10 Unit End Questions
1.11 Glossary
1.12 Suggested Readings and References
1.0 INTRODUCTION
Let us start our journey into the realm of human mind. A scientific quest for understanding will be the foremost in our journey. We want to know why we think, feel and behave as we do. What makes each of us different from all other people? Why we do often behave as alike in some situations. Psychologists, as scientists, answer these questions systematically, develop the principles to explain them and use those principles to solve various problems. They are actively engaged in process of doing research.
Research is a process through which new knowledge is discovered. A theory, such as a theory of motivation, or development, or learning, for example, helps
Introduction to Research Methods in Psychology
us to organise this new information into a coherent body, a set of related ideas that explain events that have occurred and predict events that may happen. Conducting research requires to follow a sequence of steps. The exact sequence and steps vary somewhat with the type of research. The steps vary slightly by whether a study involves a quantitative or a qualitative approach and data.
This unit attempts to acquaint you with the nature and relevance of research. This is followed by the qualities of a good research. Further, you will find the process of psychological research within the context of discovery (getting and idea) and context of justification (Testing hypothesis). This unit will provide a quick glance at the whole process of research to acquaint you with the various tasks you faced to undertake to carry out your research. It will give your some idea of what the research journey involved. Finally, this unit will cover the total spectrum of research and endeavor starting from the problem through to writing a research report and its publication.
1.1 OBJECTIVES
After reading this unit, you will be able to:
- Define research;
- Describe the meaning of research;
- Explain the relevance of research;
- Describe the process of conducting research;
- Elucidate how to evaluate a research;
- Analyse how to maintain objectivity and minimize bias in psychological research;
- Explain the role of theory, hypothesis and paradigm in psychological research;
- Enlist the various steps needed for conducting a research;
- Explain how theoretical knowledge can be further applied to undertake a research; and
- Analyse the importance of each steps involved in research process.
1.2 DEFINITION AND MEANING OF RESEARCH
The word research is composed of two syllables, re and search. The dictionary defines the former as a prefix meaning again, a new or over again and the latter as a verb, meaning to examine closely and carefully, to test and try, or to probe. Together they form a noun describing a careful, systematic, patient study and investigation in some field of knowledge, undertaken to establish facts or principles (Grinnell 1993). The simplest meaning of research is to search for facts, answers to research question and solution for the problem.
Scientific Research is a systematic and objective attempt to provide answers to certain questions. The purpose of scientific research is to discover and develop an organised body of knowledge. Therefore, scientific research may be defined as the systematic and empirical analysis and recording of controlled observation,
Introduction to Research Methods in Psychology
- To gain familiarity with a phenomenon or to achieve new insights into it (studies with this object in view are termed as exploratory research studies);
- To portray accurately the characteristics of a particular individual, situation or group (studies with this object in view are known as descriptive research studies);
- To determine the frequency with which something occurs or with which it is associated with something else (studies with this object in view are known as diagnostic research studies)’
- To test a hypothesis of a causal relationship between variables (such studies are known as hypothesis- testing research studies/experimental studies).
Thus, research is the fountain of knowledge for the sake of knowledge and an important source of providing guidelines for solving different business, personal, profession governmental and social problems. It is a sort of formal training which enables one to understand the new developments in one’s field in a better way.
1.5 QUALITIES OF A GOOD RESEARCH
Good research possesses certain qualities which are as follows: Good research is systematic : it means that research is structured according to set of rules to follow certain steps in specified sequence. Systematic research also invites creative thinking, and certainly avoids use of guessing and intuition for arriving at the conclusion.
Good research is empirical : it implies that any conclusion drawn is based upon hardcore evidence gathered from information collected from real life experiences and observations. This provides a basis for external ability to research results.
Good research is valid and verifiable : Research involves precise observation and accurate description. The researcher selects reliable and valid instruments to be used in the collection of data and uses some statistical measures for accurate description of the results obtained. Whatever you conclude on the basis of finding is correct and can be verified by yourself and others.
Good Research is logical: it suggests that research is guided by the rules of reasoning and logical process of induction (general to specific) and deduction (specific to general) that plays an important role in carrying out research. In fact, logical reasoning makes research feasible and more meaningful in the context of decision making.
Good research develops theories and principles: which are very helpful in accurate prediction regarding the variables under study. On the basis of the sample observed and studied, the researcher makes sound generalisations regarding the whole populations. Thus, research goes beyond immediate situations, objects or groups being investigated by formulating a generalisation or theory about these factors.
Research is replicable : the designs, procedures and results of scientific research should be replicable so that any person other than the researcher himself may assess their validity. Thus, one researcher may use or transit the results obtained by another researcher. Thus, the procedures and results of the research are replicable as well as transmittable.
Basic Process/Concept in
1.6 RESEARCH PROCESS: BASIC Research
CONSIDERATIONS
Before we examine what researchers have found in the major areas of psychology, we need to identify the ways psychologists gather data about behaviour and mental processes. Recall that psychology is the scientific study of behaviour and mental functioning of individuals. It is scientific because it uses the principles and practices of the scientific method.
Let us turn now how psychologists know what they know.
Empirical investigation in any field requires the use of the scientific method to observe, measure, and experiment. Even if you never do any scientific research in your life, mastering information on psychological research will be useful. You can improve your critical thinking skills by learning how to ask the right questions about behaviour and how to evaluate the answers you find.
Psychological research process can be divided into two major categories that usually occur in sequence that is (i) getting an idea [context of discovery] and then (ii) testing it (context of justification).
1.6.1 Context of Discovery
This is the initial phase of research during which observations, belief, information, and general knowledge etc., lead someone to come up with a new idea or a different way of thinking about phenomena.
1.6.1.1 Role of Theories, Hypotheses and Paradigms in Psychological
Researches
Researchers begin with the assumption of determinism, the idea that all events (physical, mental and behavioural) result from specific causal factors. Researchers also assume that behaviour and mental processes follow set patterns of relationships that can be discovered and revealed through research.
Psychological theories, in general, attempt to understand how brain, mind, behaviour, and environment function and how they may be related. Any particular theory focuses on a more specific aspect of this broad conception, using a body of interrelated principles to explain or predict some psychological phenomenon.
The value of a theory is often measured in terms of the new ideas, or hypotheses, that can be derived from it and tested. A hypothesis is a tentative and testable explanation of the relationship between two or more events or variables. A variable is any factor that changes, or varies, in size or quality. To illustrate this mood may be a variable, since people’s moods may vary from one situation to another. Test performance is another variable, since a person’s score may vary from one test to the next.
Finally, our understanding of a complex process is also aided by using the correct paradigm. A paradigm is a model of the functions and interrelationships of a process, a “way of thinking” about the world and how to study it. Entire field of knowledge, including psychology, can change directions when new paradigm challenges existing ones. When paradigms shift, revolutions of knowledge usually
Basic Process/Concept in Research
conclusions and then attempt to replicate the results. Thus, science is not a set of rules but rather a process of asking, observing, explaining, testing, and retesting explanations of reality.
1.6.2.2 Objectivity Safeguards in Research Process
This consists of (i) procedural safeguards (ii) standardisation (iii) operationa- lisation (iv) avoiding of bias. Let us take each of these and discuss.
Since subjectivity must be minimized in the data collection and analysis phases of scientific research, procedural safeguards are used to increase objectivity. These safeguards begin with keeping complete records of observations and data analyses in a form that other researchers can understand and evaluate. As a result, most scientific reports are written in a similar form and published by organisations of scientists. These reports communicate ideas to the entire scientific community and open those ideas to criticism. A second safeguard is standardisation. Standardisation means using uniform, consistent procedures in all phases of data collection. All subjects should receive the same instructions and be treated in the same way. By applying a standard treatment for all participants in the course of study, researchers ensure they will have the same basic experience.A third safeguard involves standardising the meaning of concepts, known as operationalisation. An operational definition of a concept defines that concept in terms of how it is measured or what operations produce it. Researchers must also safeguard objectivity by avoiding bias. As explained earlier, bias from external influences, personal beliefs, observers’ perspectives, and human expectations can all distort data. Researchers use various control procedures to avoid such biases and test hypotheses in ways that are fair and error-free.
Self Assessment Questions
- An investigator comes up with a new idea or a different way of thinking is known as context of discovery (True/False)
- Use of uniform consistent procedure in all faces of data collection is known as standardisation. (True/False)
- Scientific knowledge is not based on empirical evidences. (True/False)
- Psychologists should not maintain objectivity by avoiding biases. (True/False)
- Psychological researches should be replicable (True/False)
- Operational definition of a concept is not necessary in scientific research. (True/False) Answers: (1) T, (2) T, (3) F, (4) F, (5) T, (6) F
1.7 STEPS IN RESEARCH PROCESS
Research process consists of series of actions and steps needed for conducting scientific research, if the researcher follows certain steps in conducting the research, the work can be carried out smoothly with least difficulty. These steps are described as beneath—
Introduction to Research Methods in Psychology
1.7.1 Step-I: Identification of the Problem
The first and most important step for identifying a problem is asking a question or identifying a need that arises as a result of curiosity and to which it become necessary to find an answer. The psychological studies are focused on one or many of the following kinds of questions:
What are the events that cause or determine a given behaviour or response? What is the nature of behaviour or action (i.e., its structure) and how it is linked with other actions and behaviours? What are the relationships of internal psychological processes with behavioural phenomenon? The research question determines the direction of study and researchers have to struggle a lot in identifying and articulating the same. Essentially two steps are involved in formulating the research problem, viz, understanding the problem thoroughly, and rephrasing the same into meaningful terms. The main function of formulating a research problem is to decide what you want to find out about.
It is extremely important to evaluate the research problem in the light of funds, time and expertise and knowledge available at your disposal. It is equally important to identify any gaps in your knowledge of relevant disciplines, such as statistics required for analysis.
Once the question has been asked, that next step is to identify the factors that have to be examined to answer the question. Such factors might range from the most simple, such as a child’s age or socioeconomic status, to more complicated measures such as the effects of violent cartoons on a child’s behaviour. The factors may be age of the child, degree of violence in programs, emotional arousal, facial expression, family communication patterns etc. Besides this, following factors should be considered by the researcher for identifying in research problem:
Have not been investigated before; Will contribute to the understanding of your question; Are available to investigate; Lead to another question!
For identifying a good solvable problem, the investigator undertakes the review of literature. A body of prior work related to a research problem is referred to as literature. Scientific research includes a review of the relevant literature. When a researcher reviews the previous researches in related fields, he becomes familiar with several known and unknowns. Therefore one obvious advantage of review of the literature is that it helps to eliminate duplication of what has already been done and provide guidance and suggestions for further research. The main purpose of review of the literature is fourfold. First it gives an idea about the variables which have been found to be conceptually and practically important and unimportant in the related field. Thus the review of literature helps in discovering and selecting variables relevant for the given study. Second the review of the literature provides as estimate of the previous work and provides an opportunity for the meaningful extension of the previous work.
Third, a review of the literature helps the researcher in systemising the expanding and growing body of knowledge. This facilitates in drawing useful conclusions
Introduction to Research Methods in Psychology
that it is operationally defined. An operational definition involves specifying the actual operations that define a given variable. Operational definition is also important for the purpose of measurement. Since psychological variables are complex and their measurement posses special problems. Therefore, psychologists are very eager to use operational definitions. They frequently use verbal measures, behavioural measures and psychological measures of variables in their studies, which are able to help him or her to specify the operations and may allow quantification.
1.7.4 Step-IV: Formulating a Research Design
A research design may be regarded as the blueprint of those procedures which are adapted by the researcher for testing the relationship between the dependent variable and the independent variable. There are several kinds of experimental designs and the selection of any one is based upon the purpose of the research, types of variables to be controlled and manipulated as well as upon the conditions under which the experiment is to be conducted. The main purpose of experimental design is to help the researcher in manipulating the independent variables freely and to provide maximum control of the extraneous variables so that it may be said with all certainty that the experimental change is due to only the manipulation of the experimental variable. The main function of a research design is to explain how you will find answers to your research questions. The research design sets out the logic of your inquiry. A research design should include the following; logistical arrangements have to made according to proposed research design , the measurement procedures, the sampling strategy, the frame of analysis and the time frame. For any investigation, the selection of an appropriate research design is crucial in enabling you to arrive at valid findings, comparisons and conclusions. A faulty design may derive misleading findings. Empirical investigation is primarily evaluated in the light of the research design adopted. While selecting a research design it is important to ensure it is valid workable and manageable.
1.7.4.1 Constructing Devices for Observation and Measurement
When the research design has been formulated, the next step is to construct or choose appropriate tools of research for scientific observation and measurement. Questionnaire and interview schedule are the most common tools which have been developed for the psychological research. If the readymade tools are not available then the researcher may have develop appropriate tools before undertaking the study. All these tools of research are ways through which data are collected by asking for information from person rather than observing them.
1.7.4.2 Sample Selection and Data Collection
After deciding the tools for the study the researcher also decides about the participants of the study. Usually a small sample is drawn which represents the population. The participants could be children, adolescents, college students, teachers, managers, clinical patients or any group of the individual in whom/ where the phenomenon under investigation is prevalent. Depending on the nature of research problem a researcher may choose particular method (e.g. observation, experiment, case study, and survey) for data collection. The researcher also decides how the tools to be administered to collect data that is individual or group.
Basic Process/Concept in Research
In data collection phase, researcher must consider recruitment of staff and assignment to them, way of increasing response rate and cost of training of staff etc. Effect of each of these must be evaluated in terms of cost, accuracy, reliability and validity.
1.7.5 Step-V: Data Analysis and their Interpretation
After making observation the data collected are analysed with the help of various quantitative / statistical and qualitative techniques .Careful scrutiny of the data is a critical aspect of scientific method. The purpose of the analysis is to make sense of the data and see what light they throw on the problem and the hypotheses of the study and draws conclusion accordingly. Data analysis can be done by using univariate analysis in which research deals with a single characteristics of interest, bivariate analysis in which researcher deals with two characteristics of interest and by using multivariate analysis in which more then two characteristics are involves.
Depending upon the nature of data and purpose of the experiment, either a parametric statistic or a non-parametric statistic is chosen for statistical analysis. In general, the purpose of carrying out the statistical analysis is to reject the null hypothesis so that the alternative hypothesis may be accepted.
1.7.6 Step-VI: Drawing Conclusions
The investigator, after analysing the results, draws some conclusions. In fact the investigator wants to make some statement about the research about the research problem which he could not make without conducting his research. Whatever conclusion drawn, researcher generalises it to the whole population. During this phase, hypotheses are accepted or rejected. At the same time the conclusions of the study are related to the theory or research findings from which the hypotheses originally came. Depending on the new findings the original theory may have to be modified.
1.7.7 Step-VII: Preparation of Report and Publication
This is the last step in most of the research studies. The researcher documents all the steps of his or her research in clear terms this report inform that what you have done, what you have discovered and what conclusion you have drawn from findings. If you are clear about the whole process you will also be clear about the way you want to write in your report. This helps the reader to understand the study and use it for various purposes. It allows one to replicate the study. The publication of study in scientific journals or books and in public domain makes the work available for wider dissemination.
Self Assessment Questions
- The first step of research process is identifying a problem. T/F
- Hypotheses are formed after formulating a research design. T/F
- Preparation of report and publications of research study allow the other researchers to replicate the study. T/F
- An operational definition of the variables is not necessary for the purpose of measurement. T/F
- Selection of particular data collection method depends on the nature of study. T/F Answers: (1) T, (2) F, (3) T, (4) F, (5) T
Basic Process/Concept in Research
variable, formulation of research design, constructing devices for observation, sample selection and data collection, data analysis and interpretation, drawing conclusions and preparation of report and publications.
1.10 UNIT END QUESTIONS
What is research? Discuss qualities of good research.
In your opinion, what may be various criteria of a good research?
Discuss importance and relevance of psychological research.
How can you minimize research biases in psychological research?
What is the role of discovery of justification in psychological research?
List the steps involved in research process?
Explain the importance of research questions in psychological research?
What is the role of review of literature in research process?
Why formulates of hypothesis is necessary while conducting it?
How the steps in the research process do helps a person to get knowledge?
1.11 GLOSSARY
Empirical Investigation : Research that relies on sensory experience and observation as research data.
Context of Discovery : Initial phase of research during which an investigator comes up with a new idea or a different way of thinking about phenomena.
Theory : A body of interrelated principles used to explain or predict some psychological phenomenon.
Hypothesis : A tentative and testable explanation of the relationship between two or more events or variables.
Paradigm : A model of the functions and interrelationships of a process; a “way of thinking” about the world and how to study it.
Context of Justification : Second phase of research, in which results are tested and prepared for useful communication with the scientific community.
Standardisation : The use of uniform consistent procedures in all phases of data collection.
Operational definition : Definition of a concept in terms of how the concept is measured or what operations produce it.
Placebo Control : A control strategy where researchers compare those who received actual treatment with those who received only attention or a “dummy drug.”
Introduction to Research Methods in Psychology
Variable : something that can occur with different values and can be measured.
Independent Variable : a variable that represents the hypothesised “cause” that is precisely controlled by the experimenter and independent of what the participant does.
Dependent Variable : a variable that represents the hypothesised “effect “whose values ultimately depend on the values of independent variable.
1.12 SUGGESTED READINGS AND REFERENCES
Aylward, E.H., Richards, T.L., Berwinger, V.W., Nagy, W.E., Field, K.M., Grimme, A.C., Richard, A.L., Thomson, J.B. & Cramer, S.C. (2003). Instructional Treatment Associated with Changes in Brain Activities in Children with Dyslexia. Neurology, 61, 212-219.
D; Amato, M.R. (1970): Experimental Psychology. Tokoya : McGraw – Hill.
References Grinnell, Richard Jr (ed.) 1988, Social Work Research and Evaluation (3rd^ edition) Itasca, Illinois, F.E. Peacock Publishers.
Kerlinger, F. N. (1979) Foundation of Behavioural Research , New York, : H 107, Rinehart and Winstem Inc.
Kuhn, T.S. (1970). The Structure of Scientific Revolutions (2nd^ edition) Chicago : University of Chicago Press.
Kumar. R (2006) Research Methodology. New Delhi: Dorling Kingsley
McGuigan, F.J. (1990): Experimental Psychology: A Methodological Approach. New York : Printice Hall.
Shaywitz, S.E. (1996): Dyslexia. Scientific American , 275 (5) 98-104.
Townsend, J.C. (1953): Introduction to Experimental Method. Tokyo : McGraw Hill.
Introduction to Research Methods in Psychology
How can a researcher be sure that the data gathering instrument being used will measure what it is supposed to measure and will do this in a consistent manner?
This is a question that can only be answered by examining the definitions for and methods of establishing the validity and reliability of a research instrument.
Reliability and validity are central issues in all measurement. Both concern connecting measures to constructs. Reliability and validity are salient because constructs are often ambiguous, diffused and not directly observable. Perfect reliability and validity are virtually very difficult to achieve. These two very important aspects of research design will be discussed in this unit. All researchers want their measures to be reliable and valid. Both ideas help to establish the truthfulness, credibility, or believability of findings. This unit will be discussed in two parts. First part covers the concept of reliability and the definitions of reliability. This is followed by various methods of establishing reliability of a research instrument of this unit. Second part of this unit discusses the concept of validity in research. You will familiarise with the various types of validity. Finally, some problems that constitute threats to validity are described.
2.1 OBJECTIVES
After reading this unit, you will be able to:
- Define reliability;
- Describe the various methods of calculating reliability;
- Explain how test retest reliability is accessed;
- Differentiate between tests of reliability;
- Define validity;
- Describe various methods of validity;
- Identify the problems that constitute threats to internal external validity; and
- Differentiate between internal and external validity.
2.2 RELIABILITY
Meaning of Reliability The idea behind reliability is that any significant results must be repeatable. Other researchers must be able to perform exactly the same experiment, under same conditions and generate the same results. This will vindicate the findings and ensure that all researchers will accept the hypothesis. Without this replication of statistically significant results, experiment and research have not fulfilled all of the requirements of testability. This prerequisite is essential to a hypothesis establishing itself as an accepted scientific truth. For example, if you are performing a time critical experiment, you will be using some type of stopwatch. Generally, it is reasonable to assume that the instruments are reliable and will keep true and accurate time. However, scientists take measurements many times, to minimize the chances of malfunction and maintain validity and reliability. At the other extreme, any experiment that uses human judgment is always going to come under question. Human judgment can vary as individual observer may rate
Reliability and Validity (External and Internal)
things differently depending upon time of day and current mood. This means that such experiments are more difficult to repeat and are inherently less reliable. Reliability is a necessary ingredient for determining the overall validity of a scientific experiment and enhancing the strength of the results.
Reliability is the consistency of your measurement, or the degree to which an instrument measures the same way each time it is used under the same condition with the same subjects. In short, it is the repeatability of measurement. A measure is considered reliable if a person’s score on the same test given twice is similar. It is important to remember that reliability is not measured, it is estimated. For instance, if a test is constructed to measure a particular trait; say, neuroticism, then each time it is administered, it should yield same results. A test is considered reliable if we get same result repeatedly.
According to Anastasi (1957), the reliability of test refers to the consistency of scores obtained by the individual on different occasions or with different sets of equivalent items.
According to Stodola and Stordahl (1972), the reliability of a test can be defined as the correlation between two or more sets of scores of equivalent tests from the same group of individuals.
According to Guilford (1954), reliability is the proportion of the true variance in obtained test scores.
The reliability of test is also defined from another angle. Whenever we measure something, measurement involves some kind of measure. Error of measurement is generally between true scores and the observed score. However, in psychological term, word error does not imply the mistake has been made. In other words, error in psychological testing implies that there is always some inaccuracy in measurement. Hence, goal of psychological measurement remains to find out the magnitude of such error and develop ways to minimize them.
2.3 METHODS OF ESTIMATING RELIABILITY
There are number of ways of estimating reliability of an instrument. Various procedures can be classified into two groups:
External consistency procedures
Internal consistency procedures
2.3.1 External Consistency Procedures
External consistency procedures compare findings from two independent process of data collection with each other as a means of verifying the reliability of the measure. Two methods are as beneath.
2.3.1.1 Test Re-test Reliability
The most frequently used method to find the reliability of a test is by repeating the same test on same sample, on two different time periods. The reliability coefficient in this case would be the correlation between the score obtained by the same person on two administrations of the test.
Reliability and Validity (External and Internal)
develop two forms of the same test, and practical constraints make it difficult to retest the same group of individuals. Instead many test developers prefer to base their estimate or reliability on a single form of a test.
In practice, psychologists do not always have two forms of a test. More often they have only one test form and must estimate the reliability for this single group of items. You can asses the different sources of variation within a single test in many ways. One method is to evaluate the internal consistency of the test by dividing it into subcomponents.
2.3.2 Internal Consistency Procedures
The idea behind internal consistency procedures is that items measuring same phenomena should produce similar results. Following internal consistency procedures are commonly used for estimating reliability-
2.3.2.1 Split Half Reliability
In this method, as the name implies, we randomly divide all items that intends to measure same construct into two sets .The complete instrument is administered on sample of people and total scores are calculated for each randomly divided half; the split half reliability is then, the simply the correlation between these two scores.
Problem in this approach
A problem with this approach is that when the tests are shorter, they run the risk of losing reliability and it can most safely be used in case of long tests only. It is, hence, more useful in case of long tests as compared to shorter ones. However to rectify the defects of shortness, Spearman- Brown’s formula can be employed, enabling correlation as if each part were full length:
r = (2rhh)/(1 + rhh) (Where rhh is correlation between two halves)
2.3.2.2 Kudar-Richardson Estimate of Reliability
The coefficient of internal consistency could also be obtained with the help of Kudar-Richardson formula number 20. One of the techniques for item analysis is item difficulty index. Item difficulty is the proportion or percentage of those answering correctly to an item. For example – symbol ‘p’ is used to represent the difficulty index. Suppose an item ‘X’ has p=0.67.this means item ’X’ was answered correctly by 74% of those who answered the item. To compute reliability with the help of Kuder-Richardson formula number 20, the following formula is used:
N Σ pq KR-20 = ——— 1 – —— N–1 σ^2
Where
N = the number of items on the test,
σ^2 = the variance of scores on the total test,
p = the proportion of examinees getting each item correct,
q = the proportion of examinees getting each item wrong.
Kuder-Richardson formula 20 is an index of reliability that is relevant to the special case where each test item is scored 0 or 1 (e.g., right or wrong).
Introduction to Research Methods in Psychology
2.3.2.3 Cronbach’s Alpha ( ααααα )
As proposed by Cronbach (1951) and subsequently elaborated by others (Novick & Lewis, 1967; Kaiser & Michael, 1975), coefficient alpha may be thought of as the mean of all possible split-half coefficients, corrected by the Spearman-Brown formula .The formula for coefficient alpha is
N Σ σ^2 j rα = ——— 1 – ——— N–1 σ^2
Where rα is coefficient alpha (^) , N is the no. of items, σ^2 j is the variance of one item, Σσ^2 j is the sum of variances of all items, and σ^2 is the variance of the total test scores.
As with all reliability estimates, coefficient alpha can vary between 0.00 and 1.00.
Coefficient alpha extends the Kuder-Richard-son method to types of tests with items that are not scored as 0 or 1. For example, coefficient alpha could be used with an attitude scale in which examinees indicate on each item whether they strongly agree, agree, disagree, or strongly disagree.
2.4 COMPARISON OF RELIABILITY ESTIMATORS
All of the reliability estimators listed above have certain pros and cons, like for example: inter-rater is best suited when the measure involves observation, it however requires multiple observers as an alternative one can look at of rating of a single observer repeated on single occasion. It can also be used if the examiner is interested in using a team of raters.
In a situation that involves use of two forms as alternate measure of the same thing, parallel forms estimator is best suited. However, this and the internal consistency measures of reliability have constrains, i.e. one has to have multiple items engineered to measure same construct.
Cronbach’s Alpha is useful in case, where lots of items are present. The test- retest reliability is mostly employed in case of experimental and quasi- experimental designs. This also depends upon string of availability of a control group that is measured on two different occasions and until post-test is done, one does not have information about reliability. Accordingly, each one of the above mentioned estimators will give a different value for reliability. Generally, test-retest and inter-rater reliability estimates will be lower in value as compared to parallel forms and internal consistency due to involvement in measurement at different times or with different raters.
