# CC1/2

CORRECT.LP and XSCALE.LP do not explicitly state the *number of reflection pairs* that were used to calculated CC1/2..

However, the number can be calculated from the numbers available, for each resolution shell: there is the NUMBER OF UNIQUE REFLECTIONS (X), the NUMBER OF OBSERVED REFLECTIONS (Y), and the number of COMPARED reflections (Z) - the latter number is the total number of unmerged observations that contributed to the CC1/2 and the R-value calculations.

The *number of reflections pairs* that were used for the CC1/2 calculation can therefore be obtained as follows: Y-Z gives the number of unique reflections that have a single observation. The remaining (X-Y+Z) unique reflections have multiple observations, i.e. there were (X-Y+Z) reflection pairs that went into CC1/2.