Institutional explanations raise the question of whether institutions are genuinely independent causes or merely the effect of the prior factors (i.e. party system, cleavages) determining their choice. (Boix 1999; Colomer 2005; Shvetsova 2003). Checking for spuriousness of institutional effects is difficult as it requires very detailed and hard to come by information about what the motivations and information of the actors choosing the institutions.. (Benoit 2004) Kathleen Bawn, for example, attributes the original adoption of the 1949 electoral system to the knowledge that parties had about their respective electoral strength. She argues that parties derived that knowledge from the 1946-48 state-level election their seat shares in the 1949 Parliamentary Council which selected the electoral system. (Bawn 1993 968-72) Her account implies that the prior party system causes the electoral system, thus making institutional effects spurious. Erhard Lange’s far less theoretical but more detailed 883 page book provides different and in my estimation more convincing account. He also emphasizes the parties’ seat maximization as an important factor shaping their institutional preferences. (Lange 1975. 342-62) However, he cites additional factors and gives them far more weight. First, parties were not the only decision makers as the Allies and state governments also participated in the decision-making process. And these additional actors were interested in goals other than seat maximization. (Lange 1975, 376-88) Second, concerns about avoiding the extreme fragmentation and party ossification of the Weimar era played an important role for all the parties. Third, the information parties derived from the 1946-48 state level election was very unreliable for a number of reasons. Politicians did not know whether the Soviet zone would become part of the new Germany, nor did they have information where the 12 million refugees would settle and for who they would vote. Simulations run by parties proved inconclusive as the same electoral system favoring a party in one state would harm it in another. (Lange 1975, 216-18, 255, 767) Fourth, whatever party system chose the electoral system was not a natural one but, as the next section shows, the direct result of Allies party licensing. In light of this evidence, it is difficult to argue conclusively that the post 1949 electoral system was the result of the pre 1949 party system. So whatever effect the 1949 electoral system had can reasonably be attributed to institutional factors rather than to some antecedent non-institutional factors.