I am helping a nonprofit develop Promotions Guidelines for their staff of 60-100 employees. Does anybody know of good, free/low-cost resources for benchmarking data and best practices? Specifically we are looking for data on how often organizations promote employees and tenure in roles.

At some of my past employers, the promotions from within were the result of the negotiation between unions and the management. In all cases, the promotional position to be filled is open to all current employees that meet the requirements of the position. The availability of the position is announced widely throughout the organization (some even advertised in all the channels that they have used in the past to recruit its employees from the general public. The announcement limits the candidacy to only current employees of the organizations.). To avoid all sorts of "isms" the organizations establish a panel to review the application materials, to interview the top (usually 3 - 5) candidates and to recommend the top two most suitable candidates to the hiring/appointing manager.