LIFESPAN: Longitudinal Study Planner
The Longitudinal Interactive Front End Study Planner (LIFESPAN) enables researchers to sketch a longitudinal study as a SEM and examine power and/or reliability measures for hypotheses about change. Currently, LIFESPAN is limited to latent growth curve models and hypotheses about the variance of change. In future versions, we plan to add indicators and simulation tools for other hypotheses and other research designs.
LIFESPAN offers means to specify a linear latent growth curve model, display the corresponding diagram, derive reliability measures of slope effects (GRR, GCR, and ECR), to derive alternative study designs with equal reliability as measured by ECR, to graphically examine trade-offs between parameters while holding ECR constant and Monte-Carlo-simulate statistical power.
— LIFESPAN is free (as in no cost) for everyone to download and to use. Commercial distribution is strictly prohibited.
— Users of LIFESPAN agree to make reference to the original source (see below) whenever they report results that are based on its use. This applies but is not restricted to grant applications, poster presentations, paper presentations, and publications.
— Users are allowed to reproduce screenshots of LIFESPAN without asking the authors for permission under the condition that they refer to the program by citing the original source (see below).
— LIFESPAN is distributed from this website. Users are not allowed to distribute LIFESPAN in some other way without prior permission from the authors. Users who wish to distribute LIFESPAN in some other way are requested to send an email to (SPECIFY EMAIL ADDRESS HERE) in which they specify how and for what purpose they intend to distribute LIFESPAN.
— Considerable effort has been put into program development and evaluation. However, there is no warranty whatsoever. Without limiting the foregoing, the authors of LIFESPAN provide no warranty that: (a) the software will meet your requirements; (b) the software will run with in an uninterrupted, timely, secure, or error-free fashion; (c) the results obtained with the software will be effective, accurate, or reliable.
Brandmaier, A. M., von Oertzen, T., Ghisletta, P., Hertzog, C., & Lindenberger, U. (2015). LIFESPAN: A tool for the computer-aided design of longitudinal studies. Frontiers in Psychology, 6:272. doi:10.3389/fpsyg.2015.00272