Fig. 4: Regression-estimated increase in appointments and vaccinations induced by reminders.

a, b, Regression-estimated increase in appointment rates at UCLA Health within six days of the first reminder date (left panel in a, b) and vaccination rates at UCLA Health within four weeks of the first reminder date (right panel in a, b), induced by receiving a reminder (versus holdout) (a) and by receiving a reminder with ownership language (versus one without) (b) across participant subgroups in the first RCT. The full sample referred to 93,354 participants included in the analysis of the first RCT. ‘White’, subsample including 49,909 participants who identified as white (excluding Hispanic or Latino individuals); ‘minority’, subsample includes 29,784 participants who identified as Asian, Black, American Indian or Alaska Native, Native Hawaiian or Pacific Islander, other race (excluding participants whose race was unknown), and/or Hispanic or Latino. The ‘≥65 years old’ subgroup includes 84,075 participants who were at least 65 years old; the ‘<65 years old’ subgroup includes 9,279 participants under 65 years old. The ‘influenza vaccine’ subgroup includes 46,757 participants who received the influenza vaccine in either of two recent influenza seasons; the ‘no influenza vaccine’ subgroup includes 46,597 participants who did not receive an influenza vaccine in two recent influenza seasons. Extended Data Table 2, Supplementary Tables 3, 5, 6, 10, 11, 13 provide complete OLS regression results graphed here and the corresponding sample sizes. Error bars represent 95% confidence intervals of estimated increases.