What is the best way of giving Development Centre participants their feedback?

There a number of factors to considered when making this decision.
The timing of the feedback is important – it should be given as close to the Development Centre event itself, so as to be fresh & relevant in the eyes of the participant and also to be fresh and clear for the observer who has been allocated this role.

It is also important not to let a participant “stew” for a long time and to become stressed, fearing the worst, whilst waiting for the feedback.
I am presuming here that the person giving the feedback would always be one of the observers present at this subject’s specific Centre. This is important for the participant to allow them to ask questions of the observer and of course to be given credible answers and feedback from a person who directly observed their performance and who made any judgements about their effectiveness and competency.

It also needs to involve the participant’s line manager in order for the feedback to be considered in conjunction with the employee's day to day work and in the context of the ongoing and future personal development planning for each individual. This is crucial given the line manager’s overall responsibility for the personal performance and team development of their employees. This can be done but does not need to take place at the same time as the initial individual Centre feedback outlined above. However it should be done within 2 – 4 weeks of the Development Centre event or it can lose its impact and relevance.

My ideal model is to give the participant’s more or less immediate feedback about how they have done, their strengths, development areas and any potential solutions on the last afternoon of a two day Development Centre process and then to follow this feedback report up with both them and their managers within two weeks of the event.