Measurement Process in Research Methods – Scales and their Reliabilities “The best way to understand something is to try and measure it” Dr. Priyanka Singh University of Memphis What is research? Seeking systematically to add to your own body of knowledge and that of others by the discovery of non-trivial facts and insights Working systematically and recording carefully Adding to the body of knowledge - yours and others Discovery Non-trivial Types of research Empirical Literature review Case descriptions Action research Empirical Gathers field data to support (or dismiss) an idea or hypothesis Literature Review A critical and/or comprehensive review of what others have written about a topic. Case Descriptions Detailed presentation of field data gathered from observation, interview, survey, etc. normally from one organization Action Research The researcher is part of the research process and outcome - the research is reflexive and transparent - often undertaken as a change programme in the researcher’s own workplace Reliability of Latent Social-Psychological Constructs in Management Perspectives on Measurement in Social Sciences What is Measurement? Usefulness of Social Sciences Measures Scaling of Latent Psychological Constructs with Multiple Items Measurement Error The variation in the information sought by the researcher and the information generated by the measurement process employed Measurement Error Contd… Sampling Error Differences that exist between sample value and the true underlying population value Non-Sampling Error All the aspects of the research process where mistakes and deliberate deceptions can occur True Score Model A mathematical model that provides a framework for understanding the accuracy of measurement Xo = Xt + Xs + Xr Xo = Xt = Xs = Xr = observed score true score systematic error random error Which leads to Research findings Develop a construct Use the concept Utilizes the scale Which is used to create Identify the concept of interest Constitutive definition If evaluation is satisfactory, the researcher Evaluate the reliability and validity of scale Which enables the researcher to develop an Operational definition That require a researcher to Measurement scales Which enables the researcher to create Characteristics of a Good Measurement Reliability The outcome of the measurement process is reproducible (Similar results are gotten over time and across situations Validity The measurement process actually measures what it purports to measure Sensitivity The measurement process shows variability in responses when it exists in stimulus or situations Social Sciences Vs. Number Systems Social Sciences Properties of the marketing phenomenon under study vary from situation to situation Number System Properties of the number system are always the same 1 = uniqueness 2 = ordering 3 = equality of differences 4 = equality of ratio Physical Sciences Social Sciences Length, Weight Easy Ratio Scale Preference, Attitudes Most Marketing Phenomenon Fall Here Interval Scale Ordinal Scale Happiness, Creativity Very Difficult Nominal Scale Four Major Levels of Measurement Level Description Basic Empirical Operations Typical Usage Descriptive Statistics Nominal (0,1…9) Use numerals to identify objects, individuals, events etc. Determination of identity, categories Classification (M/F, Buyer/non-buyer) Frequency, Percentages, Binomial test, chi-square test Ordinal (5>4, 6<9) Provide info about the relative amount of some characteristic posed by an event Determination of order (greater or less) Rankings, ratings (preferences) Median (mean and variance metric), Percentiles, Rank-order correlation Interval (7-5 = 6-4) Intervals between consecutive points are equal Determination of equality of intervals Preferred measure of complex concepts and constructs Range, Mean, Variance, Standard deviation, P.M. correlation Ratio (9/3 = 12/4) Includes an absolute zero point Determination of equality of ratios When precision instruments are available (sales, age) Mean statistics, Coefficient of variation One Variable….All measurement Levels Nominal Are you older than 35? ( ) Yes ( ) No Ordinal How old are you? ( ) < 35 ( ) 35-55 ( ) > 55 Interval How old are you? ( ) 25 – 34 ( ) 35 – 44 ( ) 45 – 54 ( ) 55 – 64 Ratio How old are you? _________________ e.g., Likert Scale We love our customers SA A NAND D SD We have an excellent customer complaint cell SA A NAND D SD We believe in 1-2-1 marketing SA A NAND D SD In our organization products are tailored according to customer needs SA A NAND D SD SA We are not able to anticipate customer behaviour A NAND D SD Scoring a Likert Scale 0 5 1 2 -2 1 4 2 1 -1 2 3 3 0 0 3 2 4 -1 1 4 1 5 -2 2 SA A NAND D SD Overview of Dimensionality Concerned with homogeneity of items Unidimensionality vs. Multidimensionality Forms of Reliability Test-retest Reliability Internal Consistency Alternative Forms Coefficient Alpha Coefficient alpha is the basic formula for determining the reliability based on internal consistency. It should be applied to new measurement methods. Coefficient alpha sets an upper limit to the reliability. Coefficient alpha provides a good estimate of reliability in most situations because it considers sources of errors that are based not, strictly speaking, on the sampling of items per se, but on the sampling of situational factors accompanying the items. Coefficient Alpha Contd.. The reliability of scores obtained on a sample of items from a domain increases with the number of items sampled. Alpha is a function of scale length. α = kr/1+ (k-1) r where k is the number of items in the scale and r is the average correlation among the items in the scale. Selected Readings Psychometric Theory – Jum C. Nunnally (1975) Scale Development – Subhash & Bearden (2003) Thank You !!
