No matter if you call it a Institutional Improvement Plan, Institutional Assessment and Improvement Plan or even just Plan, this document MUST be a living document. You should have a committee (elected officials) within your company that have the ability to review and understand the standards for which your school must comply with to ensure you are meeting internal and external standards. This 'Plan' needs to be reviewed on a consistent basis for implementation and execution of specific benchmarks. If your plan is one or two pages long (and I have seen plans of this magnitude) my guess is that you have done the bare minimum and are not using it as a development and compliance tool.