9-19a Clinical Decision Making

Question 1

What are the differences between within group and between group differences in intervention study results?

Answer 1

Within group effects show the change measured within a group for pre- and post-intervention
Between group effects compare the changes measured in each of the intervention groups like comparing within group differences b/w intervention and control groups or b/w different interventions

Question 2

What are the differences between an absolute effect and standardized effect?

Answer 2

Absolute effect (absolute mean difference): the effect in units of within group difference (post-pre of mean values) or between group difference (mean change in group 1 - mean change in group 2)
applies clinically (MDC and MCID) and clincally applicable 

Standardized effect (standardized mean difference): compares the change across different outcome measures without units
calculated by AMD/"pooled" SD
not clinically meaningful change, but useful for comparing different outcome measures

Question 3

Differentiate between small, moderate and large intervention effects

Answer 3

0. 20 = minimal
1. 50 = moderate
2. 80 = large

Question 4

What is an effect size?

Answer 4

magnitude of the differences b/w groups

Question 5

How do standard deviation and sample size affect 95% confidence interval?

Answer 5

If sample size increases, the smaller the CI
Larger the SD, the larger the CI
The smaller the SD, the smaller the CI

Question 6

If you want to know what effect the patient should expect, what do you use:
within or between group?
absolute or standardized?

Answer 6

within group

absolute effect

Question 7

If you want to know is the intervention more effective than another:
within or between group?
absolute or standardized?

Answer 7

between group

absolute effect

Question 8

If you want to know how confident I should be in the effects:
within or between group?
absolute or standardized?

Answer 8

within group or between group

standardized or absolute effect

Question 9

If you want to compare effects across studies using different outcomes:
within or between group?
absolute or standardized?

Answer 9

between group

standardized effect

Question 10

If a patient began at 50 pts. and ended at 80 pts. and the CI were b/w 60 and 100 pts., what is the absolute mean difference and what is the CI?

Answer 10

AMD: 30 pts.
CI: 60 to 100 pts.

Question 11

If a patient began at 50 pts. and ended at 80 pts. and the CI were b/w 60 and 100 pts., what is the absolute mean difference and what is the CI?

Answer 11

AMD: 30 pts.
CI: 60 to 100 pts.

Question 12

How is the effectiveness of two groups compared between groups?

Answer 12

Intervention effect a - effect group b = net effect

Question 13

How is Confidence Interval (CI) calculated? W

Answer 13

effect +/- amount of SD * SE mean

sample size and the variability of the sample are factors

Question 14

How is the standard error of the effect calculated?

Answer 14

SD/ square root of the sample size

Question 15

How is the standard error of the mean effect calculated?

Answer 15

SD/ square root of the sample size

Question 16

What is the Z score in regards to CI?

Answer 16

It is how confident you want to be/the amount of standard deviations
the higher the Z score, the greater percent confidence the mean will fall in the CI