Sloof, R. (2000). Interest group lobbying and the delegation of policy authority Economics and Politics, 12(3):247--274.

In a signalling model of lobbying the politicians' decision whether to delegate policy authority and an interest group's choice between lobbying politicians or bureaucrats are investigated. Only bureaucrats are able to assess policy-relevant information coming from the interest group, but their interests may differ from those of politicians. In equilibrium politicians weigh the benefits of an informed policy decision against bureaucratic drift. We obtain that delegation occurs only when the bureaucracy is not too much biased and when the stakes of the interest group are not too high. Still, politicians sometimes prefer a biased bureaucracy and the interest group to have a larger stake. The model also predicts that interest groups typically lobby politicians to further delegation.