SINGLE-CASE, QUASI-EXPERIMENT, AND DEVELOPMENTAL RESEARCH

Single Case Experimental Designs (formerly called single-subject designs) Measured from baseline period to treatment periods

Reversal or withdrawal design Called an ABA design Baseline (A) Treatment (B) Baseline (A)

The use of praise as a treatment to measure the improvement of a child’s school performance

Measure test scores give regimen of praise for correct homework problems measure test scores

Multiple Baseline Designs Change is observed under multiple circumstances The manipulation is introduced at different times Determines that the manipulation caused change

Used when control features of experimental designs cannot be achieved For example, the independent variable cannot be

manipulated Internal validity may be affected

One-Group Posttest-Only Design

Nonequivalent Control Group Design

One-Group Pretest-Posttest Design

Nonequivalent Control Group Pretest-Posttest Design

Cross-Sectional Method – persons of different ages measured at the same point in time

Longitudinal Method – same group is observed at different times (as they age)

Sequential Method – combination of 1 and 2

Cross Sectional Method

Year of Birth (cohort) Time 1: 2005

Group 1 1950 55 years old

Group 2 1945 60 years old

Group 3 1940 65 years old

Longitudinal Method

Year of Birth (cohort)

Time 1: 2005

Time 2: 2010

Time 3: 2015

Group 1: 1950 55 yr 60 yr 65 yr

Sequential Method

Year of Birth (cohort)

Time 1: 2005

Time 2: 2010

Time 3: 2015

Group 1: 1950 55 yr 60 yr 65 yr

Group 2: 1940 65 yr 70 yr 75 yr

Comparison of Longitudinal and Cross-Sectional Methods Strengths:

- Can attribute changes to development- Can examine variables at a later time - As a hybrid, the sequential method shares virtues of

both methods Weaknesses:

- Expensive- Difficult- Mortality