Measurement of Concepts (Cont. 2)

Lecture 17 covers the four fundamental levels of measurement originally codified by S.S. Stevens: nominal, ordinal, interval, and ratio scales. The nominal scale classifies data into mutually exclusive and collectively exhaustive categories without rank order (e.g., gender, marital status, department). The ordinal scale introduces rank order, indicating relative standing without measuring distance between ranks (e.g., preference rankings, educational qualifications). The interval scale possesses order and equal distance between intervals, but lacks an absolute zero point (e.g., Celsius temperature, IQ scores, standard Likert scales). The ratio scale represents the highest level of measurement, possessing order, equal intervals, and a true absolute zero point, allowing ratio comparisons (e.g., income, weight, age, distance). Students examine how measurement levels determine appropriate parametric and non-parametric statistical analyses. Measurement theory and scaling techniques are demonstrated using nominal, ordinal, interval, and ratio scales to capture complex behavioral attributes. Psychometric assessment criteria, encompassing construct validity, content validity, criterion validity, and test-retest reliability, are evaluated. Survey methodology principles are explored, contrasting face-to-face personal interviews, intercept surveys, and self-administered questionnaires. The curriculum examines sampling design fundamentals, distinguishing probability sampling methods from non-probability sampling approaches. Detailed discussions of probability sampling techniques, including simple random, systematic, stratified, and cluster sampling, explain sampling error mitigation. Non-probability sampling strategies, such as convenience sampling, purposive judgment sampling, quota sampling, and snowball sampling, are critically evaluated. Experimental research designs are analyzed with focus on internal validity control, external validity generalization, and manipulation of independent variables. True experimental designs, quasi-experimental designs, and pre-experimental arrangements are contrasted regarding treatment randomization and confounding control. Students explore non-reactive research methods, examining unobtrusive measures, physical traces, content analysis, and secondary archival data utilization. Field research and observational studies are investigated to capture naturalistic human behavior, participant observation dynamics, and qualitative field notes. Historical comparative research methodologies illustrate how archival primary sources, oral histories, and comparative historical analyses generate deep contextual understanding. Focus group discussions and qualitative interviewing techniques are evaluated for exploratory depth, group synergy, and moderator facilitation dynamics.