Deck 7: Critically Appraising Quasi-Experiments: Time-Series Designs and Single-Case Designs

Question 1

The key feature of time-series designs is:

A) The use of multiple pretests.
B) The use of multiple posttests.
C) The use of multiple data points before as well as after an intervention, program, or policy is introduced.
D) None of the above.

Answer 1

The use of multiple data points before as well as after an intervention, program, or policy is introduced.

Question 2

A well-designed simple time-series design will:

A) eliminate history as a possible alternative explanation.
B) control for passage of time and regression to the mean.
C) control for selectivity biases.
D) None of the above.

Answer 2

control for passage of time and regression to the mean.

Question 3

Which is the best interpretation for the following results of a simple time-series design study evaluating the effects of a new school program that aims to decrease the number of school dropouts?

A) The intervention was effective.
B) The results appear to be attributed to an ongoing trend that was improving with the passage of time.
C) The results appear to be attributed to regression to the mean.
D) The results appear to be attributed to history.
E) All but a are correct.

Answer 3

The results appear to be attributed to an ongoing trend that was improving with the passage of time.

Question 4

Which is the best interpretation for the following results of a simple time-series design study evaluating the effects of a new school program that aims to decrease the number of school dropouts?

A) The intervention was effective.
B) The results appear to be attributed to an ongoing trend that was improving with the passage of time.
C) The results appear to be attributed to regression to the mean.
D) The results appear to be attributed to history.
E) All but a are correct.

Question 5

Which is the best interpretation for the following results of a simple time-series design study evaluating the effects of a new school program that aims to decrease the number of school dropouts?

A) The intervention was effective.
B) The results appear to be attributed to an ongoing trend that was improving with the passage of time.
C) The results appear to be attributed to regression to the mean.
D) Both b and c are correct.

Question 6

Which is the best interpretation for the following results of a multiple time-series design evaluating the effects of a new program in School A that aims to decrease the number of school dropouts?

A) The intervention in School A was effective.
B) The results for School A appear to be attributed to an ongoing trend that was improving with the passage of time.
C) The results for School A appear to be attributed to regression to the mean.
D) The results for School A appear to be attributed to history.
E) All but a are correct.

Question 7

Which is the best interpretation for the following results of a multiple time-series design evaluating the effects of a new program in School A that aims to decrease the number of school dropouts?

A) The intervention in School A was effective.
B) The results for School A appear to be attributed to an ongoing trend that was improving with the passage of time.
C) The results for School A appear to be attributed to regression to the mean.
D) The results for School A appear to be attributed to history.
E) All but a are correct.

Question 8

Which is the best interpretation for the following results of an ABAB design evaluating the effects of an intervention that aims to improve scores on a scale measuring child rearing knowledge?

A) The intervention clearly was effective.
B) The results clearly appear to be attributed to history.
C) The results could be attributed to history or could mean that the intervention had irreversible effects.
D) The results appear to be attributed to regression to the mean.
E) The results appear to be attributed to an ongoing trend that was improving with the passage of time.

Question 9

Which is the best interpretation for the following results of a multiple-baseline design evaluating the effects of an intervention that aims to increase the number of hours spent studying each week by three boys in the same cabin in a residential treatment center?

A) The intervention clearly was effective.
B) The results clearly appear to be attributed to history.
C) The results could be attributed to history or to generalization of effects.
D) The results appear to be attributed to regression to the mean.
E) The results appear to be attributed to an ongoing trend that was improving with the passage of time.

Question 10

Which is the best interpretation for the following results of a multiple-component design evaluating the effects of an intervention containing two components that aims to reduce trauma symptoms?

A) Component A was effective, and component B added nothing to the treatment effects.
B) Only component B was effective.
C) Neither component was effective.
D) Both components were effective.

Question 11

A key limitation in all single-case designs, no matter how well they control for threats to internal validity, is their extremely restricted external validity.

Question 12

The key feature of time-series designs is their use of multiple data points before as well as after a new intervention, program, or policy is introduced.

Question 13

Multiple time-series designs combine time-series logic with the logic of the nonequivalent comparison groups design.

Question 14

The AB design has the strongest internal validity of all single-case designs.

Question 15

Visual significance means that you can rule out the plausibility of rival explanations (threats to internal validity) merely by eyeballing a graph.

Question 16

The results of an ABAB design are deemed visually significant when the graph shows that improvement occurs in every phase after the first A phase, including improvement in the second baseline phase.

Question 17

In a multiple baseline design, if improvement consistently coincides with the introduction of the B phase, then history becomes far-fetched as an alternative explanation.

Question 18

The main purpose of a multiple component design is to ascertain whether any part of an intervention is unnecessary and whether any part is most responsible for the intervention's effects.

Question 19

Explain how time-series designs can provide a reasonable degree of internal validity.

Question 20

Discuss the difference between simple and multiple time-series designs and why the latter provides more internal validity than the former.

Question 21

Discuss the advantages of ABAB designs and multiple baseline designs.

Question 22

Draw graphs illustrating results of ABAB designs and multiple baseline designs that indicate that both history and intervention effectiveness can be plausible interpretations of the same graph.