## Data ## - The data generated and analysed for the study can be found at [Figshare][1]. - Please cite the data as Valkenburg, P. M., Beyens, I., Pouwels, J. L., van Driel, I. I., & Keijsers, L. (2021). Data set belonging to Valkenburg et al. (2021). Social media use and adolescents’ self-esteem: Heading for a person-specific media effects paradigm. [Data set]. ## Analyses ## The Analyses folder contains all syntax files that were used for (1) the data preparation, descriptive statistics, and graphical presentations, (2) the assumption checks, (3) the multilevel autoregressive model, (4) the exploratory analyses, and (5) the sensitivity analysis. 1. **Data Preparation, Descriptive Statistics, and Graphical Presentations** The data preparation, descriptive statistics, and graphical presenetations were performed using R. 2. **Assumption Checks** We tested the required assumption of stationarity, by investigating whether the mean of self-esteem did not systematically change over the course of the study (McNeish & Hamaker, 2020). To that end, we compared a two-level fixed effect model including day of the study as predictor of self-esteem with an intercept-only model (i.e., a model without predictors). The analyses were performed in Mplus Version 8.4. 3. **Multilevel Autoregressive Model** We tested a two-level autoregressive lag-1 model with self-esteem as the outcome, lag-1 self-esteem as the predictor, and time spent with social media as time-varying covariate, following the procedure of McNeish and Hamaker (2020). The analyses were performed using Dynamic Structural Equation Modeling in Mplus Version 8.4. 4. **Exploratory Analyses** We conducted four exploratory analyses: (1) We examined potential platform differences, by rerunning the analyses spearately for each of the three platforms (i.e., Instagram, WhatsApp, and Snapchat); (2) we examined the main model without autoregressive effects; (3) we explored whether the person-specific within-person effects of social media use on self-esteem differed for adolescents with different mean levels of social media use or different mean levels of self-esteem; and (4) we examined whether social media use and self-esteem followed an inverted U-shaped relationship. The analyses were performed in Mplus Version 8.4 (1-3) and SPSS (4). 4. **Sensitivity Analysis** We conducted a sensitivity analysis to examine the robustness of the results. Specifically, we examined whether the between-person and within-person associations would deviate from those of the full sample when excluding participants who provided potentially untrustworthy responses to the ESM questions (n=8) from the analyses. The analyses were performed in Mplus Version 8.4. [1]: https://doi.org/10.21942/uva.19249145