  We examine the question of collapse of Turok's two-parameter family of cosmic
strings. We first perform a classification of the strings according to the
specific time(s) at which the minimal string size is reached during one period.
We then obtain an exact analytical expression for the probability of collapse
to black holes for the Turok strings. Our result has the same general behavior
as previously obtained in the literature but we find, in addition, a numerical
prefactor that changes the result by three orders of magnitude. Finally we show
that our careful computation of the prefactor helps to understand the
discrepancy between previously obtained results and, in particular, that for
"large" values of $G\mu$, there may not even be a discrepancy. We also give a
simple physical argument that can immediately rule out some of the previously
obtained results.
