Country-level weighted averages of Sharing of Votes among Candidates - SMD (upper house) (jw_smdpool2) and Sharing of Votes among Candidates - MMD (upper house) (jw_mmdpool2), where the weights are the percentage of members that originate from each tier. This variable thus reflects the value of the pooling of votes for the average member sitting in the upper house. The Pool variables measure the extent to which votes among candidates from the same party are shared. The variables equal (in order of increasing personal vote incentives): (0) where pooling of votes occurs across all candidates in a party in a district; (1) where pooling of votes occurs across some, but not all, candidates in a party in a district, or, where there is vote pooling across all candidates in a party in a district, but where the average district accounts for 5% or less of a legislature's membership; (2) where no pooling of votes occurs across candidates in a party (including single-member districts).