Design is not simply about coming up with ideas but, often more importantly, picking among ideas and deciding which ones to implement. Because development resources are finite, priorities need to be set, choices need to be made.
In our thinking about participatory design, we have so far mostly discussed participation in the generation of ideas. It would be interesting to examine as well how we handle participation in the choices among those ideas, how we generate and share information about the costs of various alternatives.
One interesting source of data on these costs is redmine, the system we use to track system development. Because our programmers keep track of the time they spend on developing features and fixing bugs (that is the basis upon which they get paid), we have good data on how much we are spending on individual features. With a bit of cleanup and categorization, this data could give use a fairly accurate picture of the relative costs of various vozmob design features.
Assessment of our participatory design process should include checking whether users are aware of these relative costs, so we can gauge the extent to which they have participated meaningfully in making choices among the related features. A next step would be to figure out better ways to communicate these relative costs (including cost estimates for future features) so that vozmob users can more fully participate in design choices going forward.