Table 4.

Frequency distribution of variables used to identify missing decision tree branches

	Yes	No	NA	No available data
Related PDA	5	13	1	1
	Missing	Clear	NA	No available data
Pros and Cons logic	5	10	4	1
	Yes	Possibly yesa	No	No information available
Missing structure 1	10	1	7	1
Missing structure 2b	6	1	8	1
Missing structure 1 OR Missing structure 2c	12	2	–	–
Missing structure 1 AND Missing structure 2c	–	–	7	1

NA Not applicable

^aIndicates lack of discussion about cause which could potentially change the options, either add more or have less

^bDoes not add to 20 because each PDA was evaluated by 1 or 2 missing structure variables

^cDoes not add to 20 because values are based on contingency tables