Attrition, physical integrity and insecticidal activity of long-lasting insecticidal nets in sub-Saharan Africa and modelling of their impact on vectorial capacity

Table 4 Variance component analysis of differences between countries, LLIN brands and survey periods in factors contributing to durability

	Source of variation
	Country	LLIN brand	Time period	Country: time period interaction	LLIN brand: time period interaction
Survival of LLINs^a
σ²	1.1 (0*–3.2)	0.2 (0*–0.6)	2.8 (0*–6.7)	2.2 (0.6–3.8)	0.4 (0*–0.8)
%Total	14.6	3.2	36.0	27.9	5.2
Use of extant LLINs^a
σ²	15.6 (0*–35.8)	3.6 (0*–8.3)	0.5 (0*–2.4)	1.4 (0*–4.2)	0.0 (0*–0.0)
%Total	47.3	10.8	1.4	4.3	0*
Original cohort LLINs in use^a
σ²	10.7 (0*–25.2)	3.2 (0*–7.4)	6.6 (0*–15.2)	2.0 (0*–5.1)	0* (0.0–0.0)
%Total	33.0	9.8	20.3	6.2	0*
Mean of Logarithm of holed area
σ²	0.7 (0*–1.6)	0.4 (0*–0.9)	1.7 (0*–3.6)	0.0 (0*–0.1)	0.0 (0*–0.1)
%Total	21.5	12.3	52.6	1.1	1

σ²: Estimate of variance component (95% confidence intervals); %Total is the percentage of the total variance in the outcome
*The REML algorithm constrains the estimates of variance components to be positive. Values of zero are substituted where the algorithm did not converge on a positive value
^aProportions analysed on a logit scale

ISSN: 1475-2875