It would seem fairly unlikely that a questionnaire would be sufficient for measuring investment decision outcomes. Alternatively you may like to start with standard ratio analysis and deepen the research from there.
Your question appears to presume that investment efficiency can be measured. In practice it is much more difficult. The IMF's Public Investment Management Index (PMI) cannot be readily mapped into quantitatively into an efficiency parameter. A promising way forward would be to focus on the prospects and cost of required operations and maintenance.