casonjc1's version from 2015-06-24 14:27


Question Answer
external validity-concerns whether inferences about observed relationships will hold over variations in persons setting time or measures of the outcomes. The generalizability of casual inferences this is a critical concern for research that aims to yield evidence for evidence based nursing practice. The degree which the effects of the study hold true over variations in people conditions and settings as well as over variations in treatments and outcomes
Understand the concept of validity.Validity is the degree to which the effect that has resulted is from the hypothesized cause. A threat is anything that could serve as an alternate explanation other than that of what was being tested.
What are the strengths of the concept?When researchers introduce design features that control for potential threats the validity is strengthened and the evidence is more persuasive.
What are some of the limitations that surround the concept?If too many things are controlled for the findings will not be able to be generalized.
How can do you use the concept to increase the strength of a study.You rule out possible other causes for the effect. You control for or eliminate the variables that could be thought to be responsible other than that of which you hypothesized. RANDOMIZE!
Know what makes a study internally valid.A study is considered internally valid when alternative explanations for the effect are ruled out and eliminated
What are the threats to internal validity?Temporal ambiguity- lack of clarity of whether the presumed cause preceeds the outcome o

Selection- preexisting difference within the group
o History- the occurrence of events external to the independent variable that can effect the outcome
o Maturation- changes that result from the passage of time
o Mortality/attrition- effects are attributed to attrition (drop out)
o Testing- effects of the pretest o Instrumentation- changes in the way that data are gathered
How do they affect a study? the threatsThey compete with the independent variable. As a potential cause of the effect.
What affects external validity?+Selecting representative people enhance increase external validity. Making sure that the participants are representative of the population that you want to generalize your results to.

-Replication of the study in multiple sites or in situations that are as close to real life as possible. Do the relationships observed hold true over different types of people, settings, outcome measures and treatments,
What threat is reduced by obtaining contact information?Selection- If there are differences between the groups prior to the study taking place, these differences will continue throughout the study and may appear as a change in a statistical analysis. Addressing these differences through subject matching or randomization is highly recommended.
What threat is a one-group pretest–posttest design especially susceptible to?testing The pretest affects the post test results.

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