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Table 1 Summary of the three methods used to measure the physical condition of LLINs in this study

From: Assessing bed net damage: comparisons of three measurement methods for estimating the size, shape, and distribution of holes on bed nets

Method Description Determination of area
WHOPES Field surveyors count the number of holes in each of four categories:
1. Less than thumb-sized but greater than 0.5 cm (0.5 < diameter ≤ 2.0 cm)
2. Larger than a thumb but smaller than a fist (2.0 < diameter ≤ 10.0 cm),
3. Larger than a fist but smaller than a head (10.0 < diameter ≤ 25.0 cm)
4. Head-sized or larger (diameter > 25.0 cm)
Each hole was assigned the midpoint area of the hole size category according to the guidelines:
1.2 cm2
28.3 cm2
240.5 cm2
706.9 cm2
Note: no additional weighting was done
Image analysis ImageJ software processed digital images of each LLIN side to extract statistical data about shapes and edges, object counts, area, and location Analyse particles tool yielded area measurements in cm2 (calibrated from square pixels representing the holes)
Ruler The length, width, and location (distance from the center of the hole to the bottom and side of the net noted as x and y coordinates) were measured using a tape measure (in mm) The measured length and width were converted to area using the formula for the area of an ellipse calculated as A = π × a × b where a is ½ the length of the major axis and b is ½ the length of the minor axis