RELIABILITY OF QUANTITATIVE & QUALITATIVE RESEARCH TOOLS

DEFINITIONS OF RELIABILITY Throndike : Reliability is the consistency of a test with which it measures whatever is supposed to be measured. Test reliability is usually thought as the degree to which the test is free from compensating error. Gronlund and Linn : Reliability refers to consistency of measurement, that is how consistent test scores or other evaluation results are from one measurement to other.

CHARACTERSITICS OF RELIABILITY Consistency Accuracy Does not ensure validity

MEASUREMENT OF RELIABILITY Test-Retest method Split half method Parallel form method Rational equivalence

TEST-RETEST METHOD Same test administered twice to the same group of pupils with a given time interval between 2 tests The test scores are correlated Product moment method of correlation High correlation between 2 set of scores indicate test is reliable

LIMITATIONS Short time interval b/w two administrations – memory and practice effects (overestimate reliability) Long time interval b/w two administrations – change in behavior due to growth and maturation (underestimate reliability) To avoid this- Time interval b/w two tests should neither be very long nor be very short.

PARALLEL FORM METHOD Two alternate forms of test are used Two forms must be homogenous in all respects One form of test administered on students and on finishing immediately another form of test is supplied to same group Scores obtained are correlated which gives estimate of reliability

PRECAUTIONS Not to have items b/w two tests very similar in two tests (to avoid very high reliability) Not to have items b/w two tests very much different in two tests (to avoid very low reliability)

SPLIT HALF METHOD Test is administered once on a sample All items are arranged in increasing order of difficulty After administering test is divided into equal parts Scores are made in two sets obtained from odd numbers of items and even number of items separately Co-efficient of correlation calculated Spearman Brown formula

RATIONAL EQUIVALENCE METHOD Kuder-Richardson reliability Method based on single administration Test is homogenous in nature Correlation between items are equal All items measure same ability

FACTORS AFFECTING RELIABILITY EXTRINSIC FACTORS INTRINSIC FACTORS

INTRINSIC FACTORS Length of the test Homogeneity of items Difficulty value of items Discriminative value Test instructions

Extrinsic factors Group variability Guessing and chance errors Environmental conditions Momentary fluctuations

QUANTITATIVE & QUALITATIVE RESEARCH Quantitative research utilizes quantitative data (closed ended) and data is collected through questionnaire, tests, attitude scales, rating scales. Qualitative research utilizes qualitative data (open ended) and data is collected through questionnaire, observation, interview, schedule

QUANTITATIVE TOOLS & THEIR RELIABILITY ACHIEVEMENT TESTS Used to measure what individual has learned- present level of performance. Achievement test scores are used frequently in evaluating influences of courses of study and teacher methods. TEST-RETEST & SPLIT HALF METHOD is used to find reliability

APTITUDE TESTS Aptitude tests are used to measure person’s potential ability in an activity of specialized kind. It predicts success in some occupation, academic or training courses. Some aptitude tests are clerical aptitude test battery, a battery of mechanical aptitude test. TEST-RETEST & SPLIT HALF METHOD is used to measure reliability PARALLEL FORM METHOD is used if multiple forms of test are present

RATING &ATTITUDE SCALE Rating scale refers to a scale with a set of points which describe varying degree of dimension of an attribute being observed. Observer may be asked to judge the behavior he observes and classify it into categories. Attitude scale asses attitude and belief of an individual. Positive and negative effect associated with some object (institution,slogan,symbol,job) SPLIT HALF METHOD, PARALLEL FORM METHOD are used to find reliability

QUESTIONNAIRE Systematic compilation of questions that are administered to a sample of population from which information is desired. Both quantitative and qualitative measuring tool TEST-RETEST & PARALLEL FORM METHOD is used to measure reliability. Comparison of responses of an alternate form with original forms of questionnaire

FACTORS AFFECTING RELIABILITY OF QUESTIONNAIRE Confusing or Ambiguous Questions Prejudice regarding sample

QUALITATIVE RESEARCH TOOLS & THEIR RELIABILITY OBSERVATION Process in which one observes what is occuring in real life situation and classify, record, interpret the happenings. It is one of the oldest technique of data collection. RELIABILITY: Inter observer aggrement Single observer Reliability among different observers should be 90% or higher.

PROBLEM IN OBSERVATION When researcher is sole observer- he or she could be biased SOLUTION Engage other trained observers Other observers should be kept unaware about the purposes and hypothesis of study – BLIND Persons under observation are unaware that they are being observed – DOUBLE BLIND

INTERVIEW Process of communication and interaction in which interviewee gives needed information verbally in face to face situation. RELIABILITY: Restating questions in slightly different form Repeating the interview Different interviewers employed

Reliability of interview is affected by- Desire of interviewee to answer according to social acceptance Content and forms of question. Physical setting or other distractions Confidence of interviewee in interviewer

SECONDARY DATA Account of events provided by a person who did not directly observe the events or objects Reliability- by ensuring that: Who collected the data What were the sources of data Was the data collected by using proper methods

CONCLUSION Reliability is very important aspect of research. Without reliability one cannot think of quality research. As we have seen that if we do not apply the methods of finding out the reliability properly we will not get the data on which we can rely upon. Along with this researcher should also work to minimize the factors which affect reliability.

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