We found the solar ovens in use during approximately half of the visits. This gives us confidence that the oven use is high, but there are several unanswered questions:  

• How many times did the weather prevent oven use?
• How many times did they use the oven because they knew the promoter was coming?
• How is use distributed among the owners? Do some always use it and other never? Or do all use it 47% of the time, as the average says?