<p>There are several models for estimating prospective within-individual effects between constructs. Researchers in psychology usually pick one model and ignore the others. The objective of the present study was to show how multiverse analyses with meta-analytic aggregation can be used for assessing prospective effects. We fitted the random-intercept cross-lagged panel model (RI-CLPM), the latent change score model (LCSM), the stable trait, autoregressive trait, and state (STARTS) model, a reversed version of the RI-CLPM, as well as corresponding multilevel models (MLM) on data on trust, loneliness, and life satisfaction. The fitted models suggested diametrically different prospective effects. Meta-analytic aggregations, on the other hand, indicated increasing prospective within-individual effects between loneliness and trust and between loneliness and life satisfaction and decreasing prospective effects between trust and life satisfaction. However, a good fit of the model of spurious longitudinal associations (MoSLA) suggested that the effects may have been spurious. Analyses of within-individual prospective effects may suggest diametrically different results depending on used model. For increased rigor and transparency, we recommend researchers to use multiverse analyses with meta-analytic aggregation and the MoSLA.</p>