Research Concepts

Question 1

Research vs Audits

Answer 1

Research is designed and conducted to generate new knowledge.

Audits are designed to find out whether the quality of a service meets a defined standard.

Question 2

Null Hypothesis

Answer 2

The hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.

Question 3

Fill in the Blanks for the Levels of Evidence for Therapeutic Studies

1a - Systematic review (with homogeneity) of ———
1b - Individual RCT (with narrow confidence intervals)
1c - ———
2a - Systematic review (with homogeneity) of ———
2b - Individual Cohort Study, including low quality RCTs (e.g. < ———% follow up)
2c - “Outcomes” research; ecological studies
3a - ——— (with homogeneity) of Case-Control studies
4 - ——— (and poor quality cohort and case-control study)
5 - ——— without explicit critical appraisal or based on physiology, bench research, or “first principals”

Answer 3

1a - Systematic review (with homogeneity) of RCTs
1b - Individual RCT (with narrow confidence intervals)
1c - All-or-None study
2a - Systematic review (with homogeneity) of cohort studies
2b - Individual Cohort Study, including low quality RCTs (e.g. < 80% follow up)
2c - “Outcomes” research; ecological studies
3a - Systematic review (with homogeneity) of Case-Control studies
4 - Case series (and poor quality cohort and case-control study)
5 - Expert opinion without explicit critical appraisal or based on physiology, bench research, or “first principals”

Question 4

Explain Case-control studies and provide an example

Answer 4

Begin with the outcome and do not follow people over time. People with a particular result are chosen (the cases) and their history is used to ascertain different experiences leading up to the result. The odds of having an experience with the outcome is compared to the odds of having the experience without the outcome.

Example: non-use of bicycle helmets and risk of fatal head injury

Question 5

Define Bias

Answer 5

Any deviation of results or inferences from the truth, or processes leading to such deviation.

Question 6

What is Type I and Type II error?

Answer 6

Type I: False positive conclusion (or incorrect rejection of the null hypothesis)
Type II: False negative conclusion

Question 7

What is a p value?

Answer 7

A number that describes how likely it is to have found a particular set of observations if the null hypothesis were true.
(The smaller the p value, the more likely the null hypothesis will be rejected. e.g. p 0.05 means 5% of the time a test statistic at least as extreme as the one found would be seen if the null hypothesis were true)

Question 8

Reliability vs Validity

Answer 8

Reliability is about a method’s consistency, and validity is about its accuracy.

Question 9

Name the four main types of reliability in tests

Answer 9

-Test-retest (the same test over time)
-Interrater (the same test conducted by different people)
-Parallel forms (Different versions of a test which are designed to be equivalent)
-Internal consistency (the individual items of a test)

Question 10

Rank in order of lowest to highest the 4 levels of measurement starting with Nominal

Answer 10

1. Nominal - can only be categorised
2. Ordinal - can be categorised and ranked
3. Interval - can be categorised, ranked and have equal intervals between neighbouring data points
4. Ratio - can be categorised, ranked, have equal intervals and have a true zero point

Question 11

Accuracy vs Precision

Answer 11

Accuracy - closeness of the measured value to the true value
Precision - closeness of repeated values to each other