Table 2.
Study outcomes at end of treatment (6 weeks after initially chosen quit date).
| Outcome | SiS3a app | QGb app | CtAc | Effect size and P value, SiS3 versus | |||||||||||||||||||||||
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QG | CtA | ||||||||||||||||||||||
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Cohen dd | Cohen re | P value | Cohen d | Cohen r | P value | ||||||||||||||||||
| Primary outcomes |
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Self-efficacy (SEQ-12f): overall, mean (SD) | 78.3 (17.3) | 71.3 (17.7) | 69.0 (19.8) | 0.40 | —g | .02 | 0.50 | — | .007 | |||||||||||||||||
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Self-efficacy (SEQ-12): internal, mean (SD) | 76.5 (20.8) | 69.6 (19.4) | 66.9 (21.4) | 0.34 | — | .03 | 0.45 | — | .01 | |||||||||||||||||
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Self-efficacy (SEQ-12): external, mean (SD) | 80.2 (16.4) | 72.7 (19.4) | 70.8 (21.3) | 0.42 | — | .03 | 0.50 | — | .009 | |||||||||||||||||
| Secondary outcomes |
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Treatment acceptability | ||||||||||||||||||||||||||
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Client satisfaction (CSQ-8h), mean (SD) | 26.9 (5.3) | 26.6 (4.5) | 25.7 (5.8) | 0.06 | — | .75 | 0.23 | — | .17 | ||||||||||||||||
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System usability (SUSi), mean (SD) | 81.9 (17.1) | 79.5 (16.0) | — | 0.15 | — | .41 | — | — | — | ||||||||||||||||
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App likability rating, mean (SD) | 4.2 (1.0) | 4.1 (0.9) | — | 0.12 | — | .50 | — | — | — | ||||||||||||||||
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App satisfaction rating, mean (SD) | 4.3 (1.0) | 4.1 (0.9) | — | 0.14 | — | .42 | — | — | — | ||||||||||||||||
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Treatment feasibility | ||||||||||||||||||||||||||
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Use of smoking cessation strategies, mean (SD) | 4.1 (0.6) | 3.9 (0.6) | 4.0 (0.7) | 0.38 | — | .04 | 0.24 | — | .16 | ||||||||||||||||
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Use of positive psychology strategies, mean (SD) | 4.3 (0.6) | 4.0 (0.5) | 4.0 (0.6) | 0.55 | — | .003 | 0.42 | — | .02 | ||||||||||||||||
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Perceived impact on quitting, mean (SD) | 4.1 (0.7) | 4.0 (0.6) | 3.8 (0.7) | 0.23 | — | .20 | 0.40 | — | .01 | ||||||||||||||||
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Applying content (min/wk), median (IQR)j | 30 (20-70) | 25 (10-60) | 30 (10-60) | — | 0.17 | .13 | — | 0.12 | .34 | ||||||||||||||||
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App usek (number of days used), median (IQR)j | 33 (11-40) | 26 (11-38) | — | — | 0.07 | .42 | — | — | — | ||||||||||||||||
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App use, weeks 1-3 (min/wk), median (IQR)j | 40 (28-68) | 28 (16-50) | — | — | 0.23 | .007 | — | — | — | ||||||||||||||||
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App use, weeks 4-7 (min/wk), median (IQR)j | 35 (21-70) | 23 (14-60) | — | — | 0.17 | .06 | — | — | — | ||||||||||||||||
| Exploratory outcomes (ie, secondary proof-of-concept efficacy outcomes) |
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Positive affect | ||||||||||||||||||||||||||
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Positive affect (PANASl), mean (SD) | 37.2 (8.2) | 33.4 (9.1) | 34.0 (8.4) | 0.44 | — | .01 | 0.38 | — | .05 | ||||||||||||||||
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Desire to smoke | ||||||||||||||||||||||||||
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Craving (Brief-QSUm), mean (SD) | 14.9 (6.5) | 19.7 (10.1) | 19.7 (10.0) | –0.57 | — | .005 | –0.57 | — | .005 | ||||||||||||||||
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Attitudes toward smoking | ||||||||||||||||||||||||||
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Adverse effects (ATSn), mean (SD) | 4.4 (0.6) | 4.4 (0.6) | 4.4 (0.6) | 0.03 | — | .74 | 0.05 | — | .65 | ||||||||||||||||
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Psychoactive benefits (ATS), mean (SD) | 2.6 (1.1) | 2.8 (1.0) | 2.9 (1.0) | –0.23 | — | .17 | –0.33 | — | .1 | ||||||||||||||||
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Pleasure (ATS), mean (SD) | 2.3 (0.9) | 2.4 (0.9) | 2.7 (1.0) | –0.11 | — | .44 | –0.45 | — | .04 | ||||||||||||||||
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Positive expectancies (DCB-SFo), mean (SD) | 28.6 (26.5) | 36.0 (24.2) | 39.1 (25.6) | –0.29 | — | .12 | –0.40 | — | .08 | ||||||||||||||||
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Negative expectancies (DCB-SF), mean (SD) | 69.0 (27.6) | 71.3 (23.0) | 67.1 (24.6) | –0.09 | — | .63 | 0.07 | — | .54 | ||||||||||||||||
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Treatment effectiveness | ||||||||||||||||||||||||||
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Change in past week cigarettes (cigarettes per week), median (IQR)j | –5 (–12 to –1) | –6 (–11 to –3) | –7 (–13 to –4) | — | 0.00 | 1.00 | — | 0.02 | .97 | ||||||||||||||||
aSiS3: version 3 of the Smiling instead of Smoking app.
bQG: National Cancer Institute (NCI) QuitGuide app.
cCtA: National Cancer Institute “Clearing the Air” brochure.
dCohen d effect size, where effects are interpreted as 0.2=small, 0.5=medium, and 0.8=large.
eCohen r effect size, where effects are interpreted as 0.1=small, 0.3=medium, and 0.5=large.
fSEQ-12: Self-Efficacy Questionnaire (range 0-100, where higher scores indicate greater self-efficacy to abstain from smoking).
gNot applicable.
hCSQ-8: Client Satisfaction Questionnaire (range 0-27, where higher scores indicate higher client satisfaction).
iSUS: System Usability Scale (range 0-100, where higher scores mean greater app usability).
jOutcomes that were not normally distributed and were analyzed with Wilcoxon rank sum tests (rather than generalized linear mixed model used for all other outcomes).
kApp use is reported for all who were onboarded (SiS3 app n=80, QuitGuide app n=75).
lPANAS: Positive and Negative Affect Schedule (range 10-50, where higher scores indicate higher levels of positive affect).
mBrief-QSU: Brief Questionnaire of Smoking Urges (range 7-70, with higher scores indicating greater cigarette craving).
nATS: Attitudes Toward Smoking scale (subscale mean score range 1-5, where higher scores indicate stronger agreement with the subscale statements).
oDCB-SF: Decisional Balance Inventory for Smoking short form (subscale range 0-100, where higher scores indicate greater agreement with the pros and cons of smoking, respectively).