The method presented here is comprehensive and, in its most complete form, it allows the measurement of occupants’ opinions about the lighting, photometric quantities, power metrics, and the state of maintenance (Boyce and Eklund, 1995). It is designed to be flexible, in that any or all of these aspects can be evaluated. Here, attention is limited to the measurements of occupants’ opinions and photometric quantities. No attempt has been made to combine various measures into a single number despite the obvious attractions of a single-number index of lighting quality (Bean and Bell, 1992). Singlenumber indices are simple to use, but they inevitably involve a loss of information, which impedes understanding.