Which of the following refers to any systematic change that occurs over time in the way in which the dependent variable is assessed?

Which of the following refers to any systematic change that occurs over time in the way in which the dependent variable is assessed?

(a) Instrumentation

(b) Maturation

(c) Testing

(d) Selection

✅ Correct option: (a) Instrumentation

Explanation (200+ words):

Instrumentation refers to systematic changes in the measurement tools, observers, or procedures used to assess the dependent variable during the course of a study. This threat to internal validity occurs when different instruments are used at different times, or when observers change their criteria or level of strictness over time. As a result, observed changes in the dependent variable may be due to measurement differences rather than the effect of the independent variable. For instance, if a teacher assesses students’ performance using a strict marking scheme at pretest and a lenient scheme at posttest, improvement may reflect instrumentation rather than real learning. Similarly, changes in test difficulty, scoring rubrics, or calibration of instruments can distort results. Maturation involves natural changes within participants, testing refers to practice effects, and selection relates to group differences. Therefore, instrumentation specifically addresses changes in how measurement occurs, making it the correct answer.

10 Related PPSC Facts:

Instrumentation threatens internal validity. Observer bias causes instrumentation effects. Changing tests affects outcomes. Reliability controls instrumentation issues. Standardized tools reduce errors. Training observers improves consistency. Instrument decay affects long studies. Calibration ensures measurement accuracy. Pretest-posttest designs are vulnerable. Valid instruments measure consistently.