Figure 1

This figure illustrates the item and indicator selection stage and major process steps. Stage I begins with source items from established instruments. A Clinical Expert Panel defined indicators for each of four features of delirium, defining indicator sets for each feature (Stage II). Overlapping boxes imply that indicators are not exclusively defined from source items. That is, an item may be used to define an indicator of more than one CAM feature. At Stage III indicators were grouped into sets according to mode of collection of the source item (direct interview vs. observational). Stage IV involved psychometric modeling steps, including dimensionality assessment, factor analysis, and item response theory analyses, resulting in reduction of the indicator set and possible splitting into multiple sub-sets. Stage V indicator sets contain 5 indicators per indicator sub-set as selected by the clinical expert panel.