Power calculation: A power calculation for the Pittsburgh Sleep Quality Index (PSQI) based on a paired t-test with an alpha of 0.05, 24 pairs, a correlation of 0.8, and a standard deviation of 5.6 showed it possible to detect a minimal clinical difference of 2 with a power of 0.76. This does not account for possible drop-outs, but we expect that the inclusion of 15 control participants not exposed to CALED will increase power. Moreover, we expect that a maximum of 3 citizens will not want to participate.