  We show that in expanding regions, the scale factor measure can be
reformulated as a local measure: Observations are weighted by integrating their
physical density along a geodesic that starts in the longest-lived metastable
vacuum. This explains why some of its properties are similar to those of the
causal diamond measure. In particular, both measures are free of Boltzmann
brains, subject to nearly the same conditions on vacuum stability. However, the
scale factor measure assigns a much smaller probability to the observed value
of the cosmological constant. The probability decreases further, like the
inverse sixth power of the primordial density contrast, if the latter is
allowed to vary.
