Ch 9

Question 1

diff types of comparison

Answer 1

compare same group at different times or after an intervention
diff groups at same time

Question 2

methods to limit influence of confounding factors (5)

Answer 2

randomization, crossover, homogeneity, matching, statistical control

Question 3

who can be “blind”

Answer 3

participants, researchers, other staff, data collectors

**more blinding = less bias

Question 4

2 diff time frames

Answer 4

cross-sectional, longitudinal

Question 5

relative timing (2 types)

Answer 5

retrospective or perspective

Question 6

3 criteria for establishing causal relationships

Answer 6

temporal (requires cause to precede effect)
relationship (relationship requires an association to be shown between the cause and effect)
confounders (requires it to be proven that the effect cannot be caused by a third variable)

Question 7

3 diff types of experimental designs

Answer 7

randomized controlled trials
pre-test/post-test
crossover

Question 8

what is crossover

Answer 8

give more than one treatment but separate the treatments and use randomization to determine the ordering

Question 9

what is usual care

Answer 9

when there is a therapy in place for something and you want to compare it with the new intervention

Question 10

what is alternative treatment

Answer 10

testing out two treatments for one outcome to see which one gets better results

Question 11

is alternative treatment design ethical?

Answer 11

YES

Ethical since both treatments should benefit the patient, but if outcomes are similar the study loses power to determine if an intervention is better

Question 12

attention control condition

Answer 12

when the control group gets attention but not the intervention.

An example of this is both independent and control groups receiving education on weight loss, but the intervention group is given a supplement to take in addition to the education

Question 13

what is delayed treatment?

Answer 13

both groups receive intervention, but the control group waits until later to get it.

This option is the most ethical of the C options

Question 14

limitations of RCTs

Answer 14

inability to test all interventions in this format, the inability to randomize certain variables, and difficulties getting administrative approval to carry out a study

Question 15

what is a quasi-experimental study

Answer 15

examines an intervention but does not include randomization

the intervention is offered to everyone in a population. To perform a comparison the researchers would find another area with a similar population

Question 16

what might a quasi-experimental study call a control group?

Answer 16

comparison group

Question 17

method to increase the reliability of the results in a quasi-experimental design

Answer 17

use a time-series design (collects data over an extended period, introducing an intervention, then collecting data for a length of time)

Question 18

disadvantages of quasi-experimental designs

Answer 18

less generalizability of the findings due to increased bias, and the increased chance for confounding variables to influence the results

Question 19

nonexperimental study AKA…

Answer 19

observational study

Question 20

cohort design or prospective design begins with…

Answer 20

a presumed cause, looks for a presumed effect

Question 21

A case-control design involves starting with…

Answer 21

the effect or outcome and looking retrospectively at patient data to observe for potential causative variables

Question 22

what is a descriptive study?

Answer 22

observes for the prevalence of something without determining a relationship

Question 23

what is homogeneity?

Answer 23

a method of restricting a study to individuals who have confounding variables and subsequently canceling out the effect of the confounding variable. For instance, if age was a confounding variable then participants could be restricted to a certain age range

Question 24

what is matching?

Answer 24

developing a comparison group with the same confounding variables as the control group

Question 25

statistical power: the larger the sample size…

Answer 25

the more powerful

Question 26

what is internal validity

Answer 26

the extent it can be inferred that the independent variable causes the outcome

Question 27

threats to internal validity (5)

Answer 27

temporal ambiguity (when the cause does not occur before the effect)
selection (selecting participants rather than using randomization)
history (outside events that can influence participants cooperation with the study)
maturation (time’s effect on the outcome)
attrition

Question 28

types of studies more likely to face threats to internal validity

Answer 28

Quasi-experimental studies and correlational studies

Question 29

construct validity

Answer 29

involves inferences from the particulars of the study to the higher order constructs they are intended to represent

Question 30

Which of the following is not a factor in establishing a causal relationship? 
A) Confounders
B) Relationship
C)  Temporal
D) Sample

Answer 30

Answer D: Sample

Confounders, relationship, and temporal are the three traits of establishing a causal relationship. The sample impacts statistical power.

Question 31

Which of the following is true of a randomized controlled trial?
A) Also known as observational study
B) Uses a control group
C) Researchers select the participants
D) Retrospective

Answer 31

Answer: B, uses a control group

Randomized controlled trials use an intervention, have a control group, randomized participants, and are primary studies.

Question 32

What is a method or intervention that quasi-experimental studies can use to increase the quality of the results if it does not use a comparison group?
A) Time-series Design
B) Increase sample size
C) Randomization
D) Identify confounding variables

Answer 32

Answer A, time-series design

Quasi-experimental studies do not use randomization, otherwise it would be structured as a RCT.

Without a comparison group the biggest disadvantage of a quasi-experimental study is influences from a specific time period on the outcome. A time-series design collects time before and after the intervention to allow data to be compared to observe a change. Increasing the sample size increases internal validity but does not impact the time confounding variable. Identifying confounding variables is important but it does not change the results.

Question 33

Which of the following are methods to control a study? (Select all that apply).
A) Heterogeneity
B) Matching
C) Randomization
D) Script

Answer 33

Answer: B, C, D, matching, randomization, and script.

Homogeneity is used not heterogeneity. Matching, Randomization, Script, Blinding, and Statistical control are all methods of maintaining control in a study.

Question 34

What type of study collects data at multiple points or over an extended period of time?
A) Observational
B) Quasi-experimental
C) Randomized Controlled Trial
D) Longitudinal

Answer 34

Answer D, longitudinal

This is the definition of a longitudinal design. The other three are research design methods and are not specific to a time.