Final answer:
Idris's concern with using self-report data is that it is prone to social desirability bias because respondents may alter their answers to appear more favorable, thus compromising the data's validity. The correct option is C .
Step-by-step explanation:
Idris is concerned about using self-report data in his experiment on college students' personalities because self-report data may be subject to social desirability bias. Self-report methods, such as surveys or questionnaires, depend on individuals to accurately report their own thoughts, behaviors, and experiences. However, participants may intentionally or unintentionally give responses that are more socially acceptable or portray them in a better light, rather than being completely honest. This concern is supported by the understanding that while self-report inventories are cost-effective and easy to administer, there's an increased chance of responses being skewed due to the desire to appear socially favorable, which can compromise the validity of the data collected.
Idris may be concerned about using self-report data for his experiment because self-report data may be subject to social desirability bias. Social desirability bias occurs when respondents answer questions in a way that portrays themselves favorably, rather than providing honest answers. This bias can affect the validity and accuracy of the data collected, especially in personality research where participants may be motivated to present themselves in a positive light.