Table 1. Single predictor variable analysis of relative effectiveness (RE)^a.

Predictor variable		Log RE	SE	T	d.f.	P
Combined intervention	None	0
	Chemical	−1.362	0.823	1.65	19	0.114
	Other	−0.220	0.834	1.59	19	0.795
Combined intervention with Chemical	No	0
	Yes but chemical spraying also applied to controls	0.039	0.563	0.07	19	0.945
	Yes and chemical spraying not applied to controls	−2.079	0.775	2.68	19	0.015
Study design	Historical control	0
	Contemporary control	2.076	0.648	3.20	20	0.0045
Any intervention in controls	No	0
	Yes	0.645	0.823	0.78	20	0.442
Any intervention in controls, excluding historic controls	No	0
	Yes	−0.045	0.368	0.12	14	0.904
Time at follow-up/m		−0.081	0.042	1.93	17	0.071
Log time at follow-up/m		−1.135	0.593	1.91	17	0.073

^aNote that negative Log RE is associated with greater reduction in entomological indices in the intervention.