The past years have witnessed an increasing awareness that many animal studies are heavily underpowered. Based on a systematic search involving over 1200 articles, we estimated that at best only 12% of animal experiments are sufficiently powered. This poses a serious problem, challenging the reliability of animal models. One could increase the number of animals…

In this presentation I will discuss the do’s and don’ts related to survey design. Online surveys are being completed on a range of different devices (PC, tablet, mobile phone) and this affects optimal survey design, response rates and data quality. I will discuss survey errors and how to overcome them. Vera Toepoel Utrecht University

Longitudinal surveys which gather information from the same units at different point in time offer analytic and data collection advantages. However, there are unique drawbacks: panel attrition, whereby first wave participants discontinue participation and panel conditioning, a type of measurement error in which different answers are given in subsequent waves as a result of survey…

Sensors included on smartphones or other wearables potentially allow for the precise study of human behavior. Accelerometers typically measure movement behavior in three dimensions (x,y,z) for people at a rate of 60 times per second. Geolocation sensors measure someone physical location in latitude and longitude at a rate that in practice varies between once per…

Many psychological researchers examine the degree to which members of a dyad relate to one another. However, researchers often face challenges while attempting to identify the minimal sample size required to detect a specific dyadic effect (i.e., perform a power analysis). More specifically, researchers often have considerable challenge identifying effect sizes (e.g., exact values for…

Single-Case Experimental Designs (SCEDs) are a useful tool for evaluating therapy effectiveness in heterogeneous and low-incidence conditions. Mediation analysis informs researchers about the mechanism through which the intervention leads to changes in the outcome of interest. Hypotheses about mediated effects are often phrased in terms of within-person processes but evaluated using group-level analyses. In recent…

Academic learning as well as teaching are interactive moments, where the teacher has to ensure that students grasp the shared knowledge (Parsons, Nu- land, & Parsons, 2014). A scientific approach to teaching, that enables educators to increase their effectiveness and efficiency in sharing skills and knowledge with their students across levels, is the Interactive Direct…

If the sample size is (very) small, ML estimation in structural equation modeling (SEM) often fails even for relatively simple models. This means that the optimizer that is used in SEM software can not find a solution at all, or that the solution that is obtained contains nonsensical (often extreme) values for several parameters in…