1. Evaluation Objective vs. subjective Matching representation to:
Metrics
Formal
Cognitive
Matching representation to:
Information domain
Task of user

2. Areas of investigation
Ontology of information domain
Structure of domain
Structure of document
Ontology of document access tasks
Review of evaluation techniques for document access (e.g. NL)
Educational research

3. Dimensions of variability
Expressiveness/effectiveness
Mappings
Static vs. dynamic
Representation types
Dimensions of difference
Information types
Selection/retrieval
Focus
Secondary notation

4. HAZOPS Hazard and Operability Studies Diagram
Matches structure of domain
Structures task
Levels of abstraction/detail
Suggests provision of (range of) representations to guide/support tasks