A study reports a 60 rate of attrition among the participants. ...

[lindiwe]

A study reports a 60 rate of attrition among the participants. This finding suggests which of the following?
 
  A) A threat to internal validity
  B) Lack of recruitment
  C) Appropriate compensation/incentives
  D) Invalid measurements

Question 2

The term validity refers to which of the following?
 
  A) Truth of an inference
  B) Honesty of the report
  C) Accuracy of the measurement
  D) Preparation of the researcher

[jennafosdick]

Answer to Question 1

A
Feedback:
The study's internal validity (the extent to which a causal inference can be made) is affected by sample composition. For example, attrition can effect sample composition and thus internal validity. Were those in the intervention group more likely (or less likely) than those in the control group to drop out of the study? If so, any observed differences in outcomes could be caused by individual differences in the groups (for example, differences in motivation), rather than by the intervention itself. This does not necessarily mean that the original sample was inadequate. Compensation and incentives may have been inadequate. High attrition is not relevant to the measurements that were used.

Answer to Question 2

A
Feedback:
As the research methodology experts Shadish and colleagues (2002) have stated, We use the term validity to refer to the approximate truth of an inference (p. 34). Validity is not synonymous with honesty, though the two terms are indeed congruent. Similarly, validity is not defined as accuracy or preparation.