Which of the following designs would probably be highest in internal validity?
A) Y1      X      Y2
B) X       Y2
$\quad$---     Y2
C) (R)     X      Y2
$\quad$(R)     ---     Y2
D) Y1      X      Y2
$\quad$Y1      ---     Y2

Question

Which of the following designs would probably be highest in internal validity?
A) Y1      X      Y2
B)  X       Y2
$\quad$---      Y2
C) (R)     X      Y2
$\quad$(R)     ---     Y2
D) Y1      X      Y2
$\quad$Y1      ---     Y2

Quizplus · Accepted Answer

Design C, which includes random assignment (indicated by (R)) to experimental and control groups and measures outcomes (Y2) after the intervention (X) or no intervention (---), is typically highest in internal validity. Random assignment helps ensure that any differences in outcomes can be attributed to the intervention rather than pre-existing differences between the groups.

Which of the Following Designs Would Probably Be Highest in Internal