The OP-OD method may be applied to its full extent by private clients such as housing cooperatives. In principle, for private clients there are no obstacles in terms of public procurement. The high level of transparency of the procedure and the high degree of access to it, which are viewed as fundamental, should also be advantageous from a compliance point of view. However, issues relating to copyright (or its partial relinquishment) as well as to liability for planning outcomes, possible errors, and resulting damage, have yet to be clarified. In this regard, open questions remain, especially concerning the transition to other planning phases — such as approval procedure and detailed design. Although these questions can sometimes be answered in relation to a specific project or actor, there is still a lack of more detailed studies and recommendations on how to deal with them as a rule. Also, the changed understanding of collaborative planning and shared responsibility at the heart of OP-OD, especially as far as planners and building owners are concerned, has not yet been thought through in a legal sense as regards changed contract designs and liability mechanisms.

For public contracting authorities, on the other hand, the OP-OD method is currently only applicable to a limited extent. However, it can be used without any difficulty in its current form as a preparatory planning tool by actors subject to public procurement law. The fundamental ambition to involve users and, also, political decision-makers at an early planning stage, from 0 onwards, can thus be pursued in a new way. The method can deliver basic planning principles and initial planning variants similarly to a feasibility study. As a result, it fits in very well with the concerns of, in particular, public contracting authorities and, especially amongst them, smaller municipalities. As regards further applications and the awarding of contracts, however, adjustments will need to be made.

Necessary prerequisites for public contracting authorities

The OP-OD method breaches some of the elements of the legal requirements for the awarding of public contracts. Difficulties with the application of OP-OD to usual competitive tendering procedures arise, amongst other things, from: a violation of confidentiality requirements; possible conflicts of interest concerning persons involved in the award; the requirement for impartiality within such procedures; the principle of anonymity; and also, for example in the Federal Republic of Germany, the mandatory application of the directive for planning competitions [Richtlinie für Planungswettbewerbe – RPW 2013] or the independence of judges. Changes to (European) public procurement law to the effect that all components of OP-OD would be compliant with public procurement law are not a realistic option at the moment. Initiatives would need to be taken in other places with regard to necessary changes in support of collective and participatory procedures, or even completely different planning methods. However, there is currently no sign of this. It would be worth checking, however, to what extent modifications or additions to, for example, the RPW 2013 might allow significantly more collaborative and participatory elements. A method such as OP-OD, including its options for finding solutions, could thus be available to public contracting authorities as a fully-fledged planning tool, albeit in a slightly modified form.