  We use the Pearson cross-correlation statistic proposed by Liu and Jackson,
and employed by Creswell et al., to look for statistically significant
correlations between the LIGO Hanford and Livingston detectors at the time of
the binary black hole merger GW150914. We compute this statistic for the
calibrated strain data released by LIGO, using both the residuals provided by
LIGO and using our own subtraction of a maximum-likelihood waveform that is
constructed to model binary black hole mergers in general relativity. To assign
a significance to the values obtained, we calculate the cross-correlation of
both simulated Gaussian noise and data from the LIGO detectors at times during
which no detection of gravitational waves has been claimed. We find that after
subtracting the maximum likelihood waveform there are no statistically
significant correlations between the residuals of the two detectors at the time
of GW150914.
