How long should each phase be in a changing criterion design? ...

[NguyenJ]

How long should each phase be in a changing criterion design?
 
  A. Phases should be long enough to allow stable responding
   B. The length of the phase should be varied if possible
   C. Phases should be brief enough to see a positive response
   D. Both A and B

Question 2

What is the chief advantage of an A-B-A-B design over a simpler A-B design, assuming the independent and dependent variables are the same as well as the subject, setting, etc.?
 
  What will be an ideal response?

[yifu223]

Answer to Question 1

D

Answer to Question 2

An A-B-A-B design offers a replication of the original intervention effect found in a simpler A-B design. That is, the researcher is able to demonstrate the functional relationship between the independent and dependent variable twice (A1-B1-A2-B2) versus only the once in the A-B design.