The CDMS and EDELWEISS collaborations have combined the results of their direct searches for dark matter using cryogenic germanium detectors .
The total data set represents 614 ~ { } \mbox { $ \mbox { kg } \cdot \mbox { days } $ } equivalent exposure .
A straightforward method of combination was chosen for its simplicity before data were exchanged between experiments .
The results are interpreted in terms of limits on spin-independent WIMP-nucleon cross-section .
For a WIMP mass of 90 ~ { } \mbox { $ \mbox { GeV / c } ^ { 2 } $ } , where this analysis is most sensitive , a cross-section of 3.3 \times 10 ^ { -44 } ~ { } \mbox { $ \mbox { cm } ^ { 2 } $ } is excluded at 90 \%~ { } \mbox { CL } .
At higher WIMP masses , the combination improves the individual limits , by a factor 1.6 above 700 ~ { } \mbox { $ \mbox { GeV / c } ^ { 2 } $ } .
Alternative methods of combining the data provide stronger constraints for some ranges of WIMP masses and weaker constraints for others .