There is a wide variety of software that allows the estimation of SEM models. Examples include Amos (Arbuckle, 2009), Calis (PROC CALIS, 2009), EQS (Bentler, 2009), LISREL (Jöreskog & Sörbom, 2009), Mplus (Muthén & Muthén, 2009), Mx (Neale et al., 2006), RAMONA (Browne & Mels, 2009), sem (Fox, 2009), and SEPath (SEPath, 2009). Given this crowded field of SEM software, it is perhaps surprising that there might be room for a new SEM package. The present article announces the availability of new SEM software that is substantially different from that currently available. We believe that OpenMx fills an open evolutionary niche in the extant SEM software ecology.
