Any methodology that only looks internally at existing provision is doomed to failure. Local unmet requirements need to be investigated using any available local intelligence gathering - community profiling, front line staff who are tuned in to what is happening in the community, maintaining awareness of and contact with local organisations, and just plain old speaking to users.
All of these sources should be built in to stock provision to ensure that proper stock breadth is maintained.
The methodology therefore advises that, in parallel with adoption of the structured EBSM framework, experimentation with new stock purchase should be carried out regularly, based on the findings from local intelligence gathering exercises.
Groups of stock that are purchased to address these assumed unmet needs should have their subsequent performance tracked to test the success of the experiments.
Some clear outcomes from this will be that particular items or subject areas will not be subsequently progressed for regular spend due to the apparent lack of interest in material purchased, whereas others will be incorporated into a Library Service's stock policy plan due to the resounding success of the experiment.