Skip to main content

Table 2 Effect sizes and power for different size samples

From: Effectiveness of computer-tailored Smoking Cessation Advice in Primary Care (ESCAPE): a Randomised Trial

OR

% increase in cessation rate

Sample

% power

Lower 1.26

3.75

4350

25

  

5800

33

  

7250

40

  

8700

47

Middle 1.42

4.21

4350

54

  

5800

67

  

7250

77

  

8700

84

Upper 1.61

4.74

4350

83

  

5800

92

  

7250

97

  

8700

99

  1. Assuming a cessation rate of 3% in the control group, with the relative increases in the proportion who report continuous abstinence of 3 months or more at a 6-month follow-up in the intervention group, applying the lower, middle, and upper odds ratios of 1.26, 1.42, and 1.61 (and assuming that participants who cannot be contacted at follow up are still smoking)