Why is instrumentation a potential threat to validity in a ...

[cnetterville]

Why is instrumentation a potential threat to validity in a time-series design?
 
  A) When participants take the same measures over and over again, they tend to get better at them.
  B) When people initiate new approaches or programs, there also may be accompanying changes in the way records are made and kept.
  C) The more times something is measured, the less reliable it is.
  D) When a study is carried out over a long period of time, participants tend to drop out or leave.

Question 2

What is the term used for the potential confounding variable in a time-series study in which the measuring procedures may be inadvertently changed over time?
 
  A) measurement error
  B) history
  C) instrumentation
  D) attrition

[SVictor]

Answer to Question 1

Answer: B

Answer to Question 2

Answer: C

[cnetterville]

Thank you!

[SVictor]

Always glad to help...