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Statistical Significance
Systematic Review Methodology
Terminology
Methodology
Critical Appraisal
100
How can the confidence interval indicate that the treatment effect is statistically significant?
For a continuous outcome, the confidence interval must not include a 0. For a dichotomous outcome, the confidence interval must not include a 1.
100
Provide rigorous summary of all primary research evidence that could be found relevant to a particular focused question.
What is a systematic review?
100
What are important questions (2-3) to keep in mind when doing critical appraisal for intervention studies?
What are the results? Are the results valid? Can I apply these results?
100
When critically appraising a systematic review, where in a Forrest Plot or Blob-o-Gram do you find the confidence interval?
The horizontal line running through the blue box.
200
How can the P-value indicate that the treatment effect is statistically significant?
The p-value must be less than the significance level. For example, if the significance level is 0.05, the p-value must be less than 0.05 in order for it to indicate that the treatment effect is statistically significant.
200
Based on the following points, how would you rate the strength of methodology? An article conducted a systemic review. Only studies that related to the PICO question were included. Databases used were mentioned. Data was organized efficiently. Reference lists were present. There were two independent reviewers involved. To sum things up, a comprehensive job was done for assessing quality, studies were appropriately combined and no fatal flaws were noted
Strong
200
During a critical appraisal, we are judging the _______ of the knowledge that has been generated in the form of research.
What is quality?
200
What are some ways to ensure validity in a study?
Appropriate research design for question, random selection and allocation of participants, allocation concealment (to participants and study personnel), all participants accounted for upon completion of the study, Intention to Treat analysis, outcome measurement reliable and valid.
200
When the authors combine findings in a meta-analysis they use tests of heterogeneity, which gives them a p-value. What does a p-value great than alpha mean? Is this what we want?
A p-value greater than alpha would mean that the differences found between the studies was found at random due to various confounding variables, and not found because of a true difference. This is what we want because when combining studies we want the studies to be similar.
300
What three ways can you determine statistical significance?
• Using the significance level (α) and the P value • Calculating the appropriate test statistic • Confidence intervals
300
If pre-appraisal is missing in an article that uses a systemic review, what process can be conducted to assess the quality of the knowledge and methods of the study?
“What is critical appraisal”
300
A term synonymous to systematic review.
What is synthesis
300
What does the vertical line represent in a Blob-o-Gram or Forrest Plot? How is this used in determining statistical significance?
The vertical line represents the line of no difference. This is used in determining statistical significance because if the CI crosses the line of no difference the results are considered statistically insignificant. If CI does not cross the line of no difference it is considered statistically significant.
400
What are the steps for testing statistical significance?
• State the research hypothesis • State the null hypothesis • Select a probability of error level (alpha level) • Select and compute the test for statistical significance • Interpret the results
400
Within the critical appraisal process of systemic reviews, there is a concept that describes criteria related to large concerns and are therefore used as reasons to reject the findings in a study due to weak methodology. Examples of this concept include: one reviewer, two dependant reviewers, and absence of a methodology description. What is this concept referred to as?
“What are fatal flaws”
500
In a study investigating the effects of a new anti-itch cream, participants with minor skin rashes were randomly divided into three groups through a computer generated system. In the first group, participants received a new anti-itch cream that contained 3% hydro-cortisone. In the second group, the participants received the standard cream available over-the-counter which contains 1% hydrocortisone. The third group, members received a cream that contained 0% hydrocortisone. The participants did not know to which group they were assigned. Participants used the cream for three days to relieve itching symptoms caused by the rash. After three days, each participant’s rash was examined to determine if itching symptoms subsided. Without knowing the results of the study, would you trust them? Why or why not? Would you do anything differently?
Blinding and random allocation is good. Does not mention whether researcher was also blinded.