Fergusson 1984.

Methods	Case control study using probabilities from previous studies.
Participants	Sixty pool drownings for which pool fencing type was known.
Interventions	Fencing was not specifically defined as three or four sides; type of gate not specified.
Outcomes	Risk of drowning in fenced and unfenced pool and attributable risk percent calculated using Bayes Theorem.
Notes	Quality of previous studies used to obtain estimates of pool fencing is unknown. Small numbers thus unstable risk estimates.