In determining the average number n̄ of tracks per bubble chamber picture, for purposes of determining cross sections, one usually cannot count all tracks, but counts tracks in only some of the pictures, selected at random. An alternative procedure is described here in which the pictures are not selected at random, but are those which contain the ``interesting events.'' The average of 1/n over this ``linearly biased'' sample equals 1/n̄, where n̄ is the desired average over a random sample. The linear‐bias method has some advantages that are complementary to those of the usual random method.