Evaluation of Combined Financial Incentives and Deposit Contract Intervention for Smoking Cessation: A Randomized Controlled Trial
Table 2
Analysis of the treatment effect on primary and secondary outcomes.
Incentives only
Commitment
Precommitment
Any treatment
OR or coef. [95% CI]
value
OR or coef. [95% CI]
value
OR or coef. [95% CI]
value
OR or coef. [95% CI]
value
No demographic controls
Primary outcomes (OR)
Passed urine test at 2 m
1.36 [0.52 : 3.53]
0.53
1.98 [0.64 : 6.10]
0.23
1.86 [0.66 : 5.26]
0.24
1.62 [0.70 : 3.73]
0.26
Passed urine test at 6 m
2.48 [0.47 : 13.06]
0.29
1.23 [0.11 : 13.96]
0.87
4.68 [0.88 : 24.91]
0.07
2.82 [0.61 : 12.97]
0.18
Secondary outcomes (OLS coefficients)
Total support counselling sessions attended
0.25 [-0.66 : 1.16]
0.59
-0.21 [-0.80 : 0.38]
0.48
-0.06 [-0.82 : 0.69]
0.87
0.07 [-0.55 : 0.69]
0.82
Total support prescriptions given
-0.17 [-0.53 : 0.19]
0.35
-0.24 [-0.59 : 0.12]
0.20
-0.31 [-0.75 : 0.13]
0.17
-0.22 [-0.53 : 0.08]
0.15
With demographic controls
Primary outcomes (OR)
Passed urine test at 2 m
1.71 [0.53 : 5.51]
0.37
3.24 [0.86 : 12.25]
0.08
3.03 [0.85 : 10.79]
0.09
2.31 [0.81 : 6.60]
0.12
Passed urine test at 6 m
0.89 [0.13 : 6.03]
0.90
0.84 [0.06 : 11.07]
0.89
4.08 [0.70 : 23.90]
0.12
1.65 [0.33 : 8.37]
0.54
Secondary outcomes (OLS coefficients)
Total support counselling sessions attended
0.08 [-0.74 : 0.89]
0.86
-0.16 [-0.93 : 0.61]
0.68
-0.36 [-1.14 : 0.43]
0.37
-0.09 [-0.66 : 0.48]
0.75
Total support prescriptions given
-0.16 [-0.52 : 0.21]
0.40
-0.19 [-0.58 : 0.20]
0.34
-0.33 [-0.70 : 0.04]
0.08
-0.21 -0.52 : 0.09]
0.17
Note: usual care is the reference group. Logistic regressions for the binary outcomes “passed urine test at 2 m” and “passed urine test at 6 m” and ordinary least squares (OLS) for the remaining outcomes. OR refers to the odds ratio from a logistic regression, and coef. refers to the coefficient from an OLS regression. Demographic controls include age, sex, an indicator for high school as the highest education level, and income bin indicators.
