Outdoor programming models, like models in other disciplines, cannot easily be defined in neat packages. Each model exists in different forms. Yet each identifies with one particular approach. For instance, Rennie has described relative degrees of common adventurism. The same is true for clubs, instructional programs, etc. To help show the differences between the various models, Blaesing used a continuum (10) which was based on the structure of trips either participant-initiated or organization-initiated. For this discussion, the following continuum will be utilized which resembles Blaesing's, but has been modified to represent a more accurate picture of the models described within.