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Foundations of Research Methods - pages 4-29 - Research design and causality - b Internal validity

35 important questions on Foundations of Research Methods - pages 4-29 - Research design and causality - b Internal validity

What is the key question in internal validity?

Whether observed changes can be attributed to you program or intervention (the cause) and not to other possible causes (described as alternative explanations for the outcome).

How do you establish internal validity?

Through the research design you apply. A specific research design can address particular issues and help you eliminate the alternative explanations for your results, thereby enhancing the internal validity of your causal conclusions.

What are the characteristic of internal validity?

Is only relevant to the specific study in question
is not concerned with whether the program you implemented was what you wanted to implement or whether what you observed was what wanted to observed
is possible to have internal validity in a study and not have construct or external validity

What are single-group threats?

Challenges that may be raised when you are only studying a single group that receives your program.

What are social threats?

Threats that arise because social research is conducted in real-world human contexts where people will react to not only what affects them, but also to what is happening to others around them.

What is a pretest-posttest single group design?

The participants are first tested on a pretest or baseline measure, then provided the program or treatment, and finally tested again with a posttest

What is a single-group design?

Research design that involves only a single group in measuring outcomes

What are history threats?

When some event other than your program occurs at the same time and affects the outcome

What are maturation threats?

When there is a change in a desired outcome level or a change in outcome, due to normal maturation or internal growth in the outcome rather than as a result of your program.
consists of all of the changes in the outcome that would occur naturally with the passage of time.

What is the difference between history threats and maturation threats?

While history threat is due to an external event or occurrence, a maturation threat comes into play due to internal changes in a person.

What is a testing threat?

When the pretest or the baseline testing experience becomes the treatment rather than the actual program (only occurs in a pre-post design).

What are characteristics of an instrumentation threat?

Only in a pretest - posttest situation (like testing threat)
part or all of any pre-post gain is due to the change in instrument, rather than to your program
is also likely when the instrument is essentially a human observer (tired or bored overtime)
Change in instrumentation leads to the outcome

What is a mortality threat?

Refers to people dropping out of your study

What is another name for mortality threat?

Selective attrition

What is a regression threat?

A statistical phenomenon that falsely makes it appear that your group changed to be more like the overall population between the pretest and posttest.
means that the pretest average for the group in your study will appear to increase or improve (relative to the overall population) even if you don't do anything to them, even if you never give them a treatment.
You can only go up or down from phenomenon

How do you deal with these single-group threats to internal validity?

Through research design
incorporate a second group (control group): one group receive the program and the other one doesn't (it becomes a multiple-group design)

What is the key internal validity issue of the multiple-group design?

The degree to which the groups are comparable before the study.

What is the only multiple-group threat to internal validity?

That the group were not comparable before the study. This is also called a selection bias or selection threat.

What is a selection threat?

Any factor that leads to differences between the groups at the start of the study.

What is selection-history threat?

- Any other event that occurs between pretest and posttest that influences the treatment and control groups differently
- The way the groups differ is with respect to their reactions to certain historical events that may occur between the pretest and the posttest.
- Example: low-income folks (no health insurance) stop smoking and high-income folks (health insurance) do not stop smoking in the antismoking cessation group after reading the Surgeon General's report about health consequences of smoking.

What is the difference between history and maturation threats?

History refers to a discrete event or series of events, whereas maturation implies the normal, ongoing developmental process that takes place.

What is selection-testing threat?

When a differential effect of taking the pretest exists between groups on the posttest

What is selection-instrumentation threat?

- Any differential change in the test used for each group from pretest to posttest
- The test changes differently for the two group

What is selection-mortality threat?

When there is differential nonrandom dropout between pretest and posttest.

What is selection-regression threat?

- When there are different rates of regression to the mean in the two groups.
- It might happen if one group was more extreme on the pretest that the other.

What are the advantages when you move from a single group to a multiple group?

If the second group is a controle group and is comparable to the program group, you can rule out entirely the single-group threats to internal validity because those threats will all be reflected in the comparison group and cannot explain why posttest group differences would occur.

How can you create two groups that are truly comparable?

The best way to do that is to randomly assign persons in your sample into the two groups - that is, you conduct a randomized or true experiment.

What are social threats to internal validity?

The social pressures in the research context that can lead to posttest differences not directly caused by the treatment itself.

What are the major social interaction threats to internal validity?

Diffusion or imitation of treatment
Compensatory rivalry
Resentful demoralization
Compensatory equalization of treatment

What is compensatory rivalry?

When the comparison group knows what the program group is getting and develops a competitive attitude with the program group.

What is resentful demoralization?

Participants in the comparison group knows what the program group is getting and the group members become discouraged or angry and give up.

What is compensatory equalization of treatment?

When the control group is given a program or treatment designed to make up for or "compensate" for the treatment the program group gets. By equalizing the group's experiences, this threat diminishes the researcher's ability to detect the program effect.

How can you minimize the social interaction threats?

- By constructing multiple groups that are unaware of each other (for example, a program group from one organization or department and a comparison group from another)
- By training administrators in the importance of perserving group membership and not instituting equalizing programs ( researchers will never be able to eliminate entirely the possibility that human interactions are making it more difficult to assess cause-effect relationships)

What are the four alternative ways to minimize any threats to any type of validity?

By argument
By measurement or observation
By analysis
By preventive action

What is the most straightforward way to rule out a potential threat to validity?

To make an argument that the threat in question is not a reasonable one. Such an argument may be made either before the fact or after the fact. The former usually is more convincing than the latter. In most cases, ruling out a potential threat to validity by argument alone is weaker than using other approaches.

The question on the page originate from the summary of the following study material:

Research Methods: The essential knowledge base | 9781133954774 | Trochim, et al

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Foundations of Research Methods - pages 4-29 - Research design and causality