A paper of mine, about feedback in Agile / XP projects, has been published on the AYE Conference website: http://www.ayeconference.com/Articles/Secretofagile.html. That paper concentrated on testing and customer involvement, but there is more feedback possible: there is feedback from members of the developer team, management, QA, and other stake-holders associated with the project.
The Standish group, in their Chaos Report, reports that the top three project success factors, in order of most important to less important are:
- User Involvement
- Executive Management Support
- Clear Statement of Requirements
Other success factors that also support my point are:
- Realistic Expectations
- Smaller Project Milestones
- Competent Staff
- Clear Vision and Objectives
In typical waterfall projects, user involvement is only at the first and last stages: requirements gathering and final testing (and sometimes users are not involved even in those two stages!). This obviously isn't enough, since IT projects, according to the Standish group, are only successful an average of 12% of the time.
Agile methods aim for success by requiring more user involvement through the life of the project: the practices of On-Site Customer and Frequent Releases, among others. User involvement also helps with maintaining realistic expectations and getting those requirements clearly understood.
Even with user involvement, there are project failures from lack of management support. Most of the stories of unsuccessful projects I've heard at BayXP are due to lack of executive management support - failure to get buy-in from the rest of the company. In some cases, the project was on-time and on-budget, but the rest of the company rejected the process and/or the people involved.
Successfully adopting XP requires a company culture compatible with its values, and many companies just don't have that culture. To get to XP, the company would need a culture change, which requires skilled, dedicated, change artists and a company-wide perceived need for change. Thus, Industrial XP does a Readiness Assessment to see if there is a culture fit.
Agile methods have smaller project milestones, a proven success factor, as well as frequent releases. Getting the product out in front of real users not only enables more feedback, but can be financially rewarding as well, by reducing time-to-market or opening a new market. For internal projects, "small releases" to some portion of the end-users is a proof of concept, demonstrating to management the viability of the project.
Competent staff is a sticky point. No method can work well if the people don't know how to do it or don't understand it. Many XP project failures result from staff that had no training on the practices and didn't practice all of the recommended practices. I've already written that XP's test-driven-development requires testing skills and refactoring skills that both inexperienced and experienced programmers may be lacking. Training and practice, whether by intensive, disciplined, self-training, or training from good teachers, is necessary for those new to XP.
Lack of competence in test-driven-development shows up in unexpectedly-failing acceptance tests, bugs slipping through to users, and decreasing velocity (features done per iteration). Developers puzzling over the bug-reports, unhappy users and managers, and increasingly-unmaintainable code probably realize that something is going wrong, but without a coach or someone experienced in software development, may not know how to fix it. In the worst cases, they ignore this feedback and deny that anything is going wrong.
Industrial XP's additional practices - Project Chartering, Project Community, Test-Driven Management, and so on - address the factors of ownership and clear vision. If the project starts to drift off course, members of the project community can point to the Charter and Manager-Tests and ask "why are we moving in this direction?" IXP's practice of doing Retrospectives regularly (mini-retrospective each iteration, as well as larger ones at longer intervals) will also help with clear vision of the objectives and ownership of the process, providing feedback to the participating members of the project community.
The hardest kind of feedback to specify in a "process" is personal feedback from people in the team, whether in pair programming, retrospectives, or otherwise.
Naomi Karten's book on Communication Gaps can help.
Many people I respect recommend What Did You Say?: The Art of Giving and Receiving Feedback by Charles N. Seashore, Edith Whitfield Seashore and Gerald M. Weinberg.
Norman L. Kerth wrote the definitive book on Project Retrospectives, but you shouldn't try to do a large retrospective without a skilled facilitator. Read the book to see why.
The larger community is also a valuable source of feedback and learning. Go to your local Agile or XP group meetings, join or at least read the XP, IXP, and/or TDD mailing lists. Read the books. Read the web. Go to conferences if you can.