While the Federal Constitutional Court of Germany (FCC) has a veto
power in legislation due to judicial review on behalf of judicial independence, the judges constituting FCC are appointed by the Federal Parliament and Federal Council. This ambivalent situation seems to be well captured by a principal agent (PA) theoretical model in which political parties correspond to principals and judges to agents. We argue that political parties can select judges close to their ideological orientation in the nomination process (screening strategy). To evaluate this, we apply an alternative class of item response theoretical model to dissenting opinions in FCC to identify individual judges' ideological orientation and the court's decision on the same ideological dimension. By comparing the judges' position with court's decisions, we can evaluate if and to which extent the
individual judges are in line with or deviate from the nominating party's ideological orientation. In our framework, the degree of judges' deviation from the party's ideological orientation should be attributed to the screening failure. The result of a beta-regression model provide some evidence that the duration after appointment and missing party membership leads to the screening failure.
