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.Get Started!
A preliminary manual describing the basic functions is available here: Longitudinal Study Designer.pdf
Read more on optimal design: 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
Read more on optimal design with planned missing data: Brandmaier, A. M., Ghisletta, P., & von Oertzen, T. (2020). Optimal planned missing data design for linear latent growth curve models. Behavior Research Methods, 52, 1445–1458. https://doi.org/10.3758/s13428-019-01325-y
The LIFESPAN program is based on Onyx, our free Structural Equation Modeling program: Find out more at onyx-sem.com
JavaTM Runtime Environment (J2RE), version 1.6 or higher, needs to be installed on your system. You can download it from Oracle for free here: https://java.com/getjava
2.Download & Installation
Please download the most recent version of LIFESPAN from this site.
Run the program by double-clicking on studydesigner.jar in your downloads folder or if you have access to a terminal by issuing the command:
java -jar lifespan-release.jar
A detailed user guide can be downloaded from this site.