Answer to Question 1
A causal inference can only be supported when very specific causal evidence exists. Three critical pieces of causal evidence are:
(1) Temporal sequence - deals with the time order of events. The cause must occur before the effect.
(2) Concomitant variation - occurs when two events covary, meaning they vary systematically. This means that when a change in the cause occurs, a change in the outcome also is observed.
(3) Nonspurious association - means that any covariation between a cause and an effect is true and not simply due to some other variable.
Answer to Question 2
B
Concurrent validity evaluates a measure by comparing it to another measure of a phenomenon, with both measures taken at the same time. It is excellent for validating a new measurement instrument with another that has already been established.
