Table 2.
Meta-Analytic Findings for Associations between Delay Discounting and Type of Addictive Behavior, Type of Dependent Variable, and Discounting Measure
| Variable | # ES | N | r | pr | rOSR | Q | pQ | I2 |
|---|---|---|---|---|---|---|---|---|
| I. Overall Effect Size | 138 | 11,395 | .14 | <10−14 | .14–.14 | 443.35 | <10−14 | 69.10 |
| II. Addictive Behavior Type | ||||||||
| Alcohol | 53 | 7,365 | .14 | <10−14 | .13–.15 | 143.04 | <10−9 | 63.65 |
| Tobacco | 40 | 2,714 | .17 | <10−11 | .16–.17 | 61.07 | .01 | 36.13 |
| Gambling | 21 | 2,940 | .16 | <10−5 | .15–.18 | 75.39 | <10−7 | 73.47 |
| Cannabis | 12 | 2,654 | .10 | .04 | .08–.13 | 69.67 | <10−9 | 84.21 |
| Stimulants | 9 | 1,649 | .05 | .48 | .01–.09 | 29.87 | <.001 | 73.22 |
| Between Category Difference | – | – | – | – | 4.92 | .30 | – | |
| III. Dependent Variable Type | ||||||||
| Severity | 69 | 9,492 | .17 | <10−14 | .16–.17 | 191.11 | <10−14 | 64.42 |
| Quantity-Frequency (QF) | 69 | 7,100 | .11 | <10−9 | .10–.11 | 193.00 | <10−14 | 64.77 |
| Between Category Difference | – | – | – | – | 6.49 | .01 | – | |
| IV. Discounting Measures | ||||||||
| MCQ | 63 | 6,954 | .14 | <10−13 | .13–.15 | 263.19 | <10−14 | 76.44 |
| Task-Based | 75 | 4,571 | .14 | <10−14 | .14–.15 | 172.36 | <10−14 | 57.07 |
| Between Category Difference | – | – | – | – | 0.01 | .90 | – | |
Note. # ES = number of effect sizes included in each category; N = total number of unique individuals represented in each category; r = Pearson’s r effect size statistic; pr = significance value corresponding to Fisher’s Z transformation of the r statistic; rOSR = range of effect sizes obtained from one-study-removed analysis; Q = Cochran’s Q test of homogeneity; pQ = p value corresponding to Cochran’s Q; I2 = proportion of variability due to heterogeneity; MCQ = 27-item monetary choice task.