TABLE III.
Fully Disaggregated Treatment Effects of Night Sleep and Nap Treatments
| Overall | Work | Well-being | ||||||
|---|---|---|---|---|---|---|---|---|
| Index | Earnings | Productivity | Labor supply | Output | Index | Physical | Psychological | |
| (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | |
| Devices+Encouragement only | 0.00 | −0.07** | −0.02 | −0.06* | −0.07** | 0.13*** | 0.16** | 0.02 |
| (0.07) | (0.03) | (0.03) | (0.04) | (0.03) | (0.05) | (0.07) | (0.09) | |
| Devices+Incentives only | −0.05 | −0.07* | −0.02 | −0.08** | −0.08** | 0.05 | 0.08 | −0.02 |
| (0.07) | (0.04) | (0.03) | (0.04) | (0.03) | (0.05) | (0.06) | (0.09) | |
| Nap only | 0.11 | −0.07 | −0.01 | −0.07* | −0.05 | 0.18*** | 0.16** | 0.19** |
| (0.07) | (0.04) | (0.03) | (0.04) | (0.04) | (0.06) | (0.07) | (0.10) | |
| Devices+Encouragement and nap | 0.13* | −0.07* | 0.04 | −0.15*** | −0.04 | 0.13*** | 0.11* | 0.11 |
| (0.07) | (0.04) | (0.03) | (0.04) | (0.03) | (0.05) | (0.06) | (0.09) | |
| Devices+Incentives and nap | 0.08 | −0.07* | 0.04 | −0.17*** | −0.07** | 0.10** | 0.11* | 0.07 |
| (0.06) | (0.04) | (0.03) | (0.04) | (0.03) | (0.05) | (0.07) | (0.09) | |
| Participants | 451 | 451 | 451 | 451 | 451 | 452 | 452 | 452 |
| Devices+Encouragement only | −0.00 | −0.00 | 0.04 | −0.09 | −0.05 | −0.10 | −0.15 | |
| (0.07) | (0.07) | (0.17) | (0.06) | (0.12) | (0.09) | (0.13) | ||
| Devices+Incentives only | −0.03 | 0.04 | −0.12 | −0.04 | 0.11 | −0.16* | −0.06 | |
| (0.08) | (0.07) | (0.19) | (0.07) | (0.12) | (0.08) | (0.13) | ||
| Nap only | 0.09 | 0.07 | 0.15 | −0.01 | 0.12 | −0.09 | −0.01 | |
| (0.07) | (0.07) | (0.17) | (0.07) | (0.12) | (0.09) | (0.14) | ||
| Devices+Encouragement and nap | 0.05 | 0.13* | 0.03 | 0.09 | 0.23* | 0.03 | 0.03 | |
| (0.08) | (0.07) | (0.18) | (0.07) | (0.12) | (0.10) | (0.13) | ||
| Devices+Incentives and nap | 0.14** | 0.09 | 0.32** | 0.01 | 0.11 | −0.10 | 0.01 | |
| (0.07) | (0.07) | (0.16) | (0.07) | (0.12) | (0.09) | (0.14) | ||
| Participants | 452 | 452 | 429 | 452 | 452 | 415 | 415 | |
Notes. This table shows the treatment effects of the five fully disaggregated treatment arms on the overall index as well as the four families of outcomes: work, well-being, cognition, and preferences. Each row shows coefficients of treatment cells compared to the control group that receives no sleep-related treatments. All work-related regressions are conducted at the participant-day level using equation (1). All other regressions are at the participant level using equation (2). The overall index (column (1)) aggregates across the four family-level outcomes. The work outcomes include data entry earnings (the summary variable for the work family, column (2)); productivity (output per hour typing, column (3)); active typing time (column (4)); and output (column (5)). Well-being outcomes include an overall index (column (6)) of the two broad measures of well-being: a physical well-being index (column (7)) and a mental well-being index (column (8)), as described in Section III.B. Cognition measures include an overall index (column (9)) of two measures: lab measurements of attentiveness, memory, and inhibitory control (column (10)); and attention to piece rates in the data entry task (column (11)). Preference measures include an index (column (12)) of three different categories: time preferences (savings, which additionally control for the surveyor on site, and present bias, column (13)), social preferences (column (14)), and risk preferences (column (15)). All indices are a weighted average of their components, in which the weights take into account the covariance structure of the components (Anderson 2008). All dependent variables are normalized with respect to the control group’s mean and standard deviation. When required, outcomes are flipped so that a positive value aligns with what would be considered a “better” outcome. Standard errors in parentheses are robust to heteroscedasticity and clustered at the participant level when applicable. Stars next to coefficients reflect unadjusted p-values (* significant at 10%; ** at 5%; *** at 1%). Online Appendix Table A.VII shows p-values that take into account multiple-hypothesis corrections.