  Few statistically compelling correlations are found in pulsar timing data
between the size of a rotational glitch and the time to the preceding glitch
(backward waiting time) or the succeeding glitch (forward waiting time), except
for a strong correlation between sizes and forward waiting times in PSR
J0537-6910. This situation is counterintuitive, if glitches are
threshold-triggered events, as in standard theories (e.g. starquakes,
superfluid vortex avalanches). Here it is shown that the lack of correlation
emerges naturally, when a threshold trigger is combined with secular stellar
braking slower than a critical, calculable rate. The Pearson and Spearman
correlation coefficients are computed and interpreted within the framework of a
state-dependent Poisson process. Specific, falsifiable predictions are made
regarding what objects currently targeted by long-term timing campaigns should
develop strong size-waiting-time correlations, as more data are collected in
the future.
