  We present an analysis of the far-infrared (FIR)-radio correlation within a
group of nearby star-forming galaxy disks observed as part of the {\it Spitzer}
Infrared Nearby Galaxies Survey (SINGS). In our study we critically test a
phenomenological model for the FIR-radio correlation which describes the radio
image as a smeared version of the infrared image. The physical basis for this
model is that cosmic-ray electrons (CR electrons) will diffuse significant
distances from their originating sources before decaying by synchrotron
emission. We find that this description generally works well, improving the
correlation between the radio and infrared images of our four sample galaxies
by an average factor of $\sim$1.6. We also find that the best-fit smearing
kernels seem to show a dependence on the ongoing star formation activity within
each disk. Galaxies having lower star formation activity (NGC 2403 and NGC
3031) are best-fit using larger smearing kernels than galaxies with more active
star-forming disks (NGC 5194 and NGC 6946). We attribute this trend to be due
to a recent deficit of CR electron injection into the interstellar medium of
galaxies with lower star formation activity throughout their disks.
