Reported walking time and measured distances to water sources: Implications for measuring Basic Service

Transcription

1 Reported walking time and measured distances to water sources: Implications for measuring Basic Service Anna Murray1, Maeve Kennard1, Daniele Lantagne2 1, 2Tufts University UNC Water and Health 2018

2 Background 2

3 Background SDGs now take into account water collection time to meet basic service (includes walking and queueing time) Impact on water collection volume, health outcomes (Overbo et al, 2016) 3

4 Background SDGs now take into account water collection time to meet basic service (includes walking and queueing time) Impact on water collection volume, health outcomes (Overbo et al, 2016) People are largely unconvinced that households estimated time is an accurate indicator of actual time (Pearson, 2016) or actual distance 4 traveled (Ho et al, 2014).

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6 Background Other methods piloted in the literature: Sensors or GPS units affixed to water collection containers to measure actual overland distance traveled (Pearson, 2016) Spatial video (Smiley et al, 2017) GIS models of straight-line vs route distances vs reported time (Ho et al, 2014) Most of these were done in one country context 6

7 is a fundraising organization and donor to WASH organizations 100% Model Private donors fund our operating costs so 100% of public donations go straight to the field. Proving It We prove every water project we build using photos and GPS coordinates on Google Maps. Our Local Partners We work with strong, local implementing partners on the ground to build and maintain water projects. 7

8 is a fundraising organization and donor to WASH organizations Our partners have been monitoring simple indicators of water access since 2014 Have 18,028 household surveys across 10 countries with 7 implementing partners, collected from

9 Aims of this work Given simple monitoring data already collected by partners across several countries: 9

10 Aims of this work Given simple monitoring data already collected by partners across several countries: 1) Does household reported walking time correlate to measured distance between the household and water point? 10

11 Aims of this work Given simple monitoring data already collected by partners across several countries: 1) Does household reported walking time correlate to measured distance between the household and water point? 2) Does reported collected volume correlate with reported walking time? 11

12 1 2 Methods

13 Data collection methods Surveys conducted by charity: water implementing partners 10% of funded water points selected, and 10 households Mali Niger Nepal Bangladesh surveyed per location Simple household survey with 12 questions, and GPS coordinate Conducted at baseline and endline of the funding period Uganda Ethiopia Kenya Rwanda Malawi Mozambique GPS coordinates of completed water points captured by partners 13

14 Analysis methods Great-circle distance was calculated from: Household GPS (from surveys) to Water source GPS (from completion coordinates) with the Haversine formula Analysis to explore: 1) Measured distance versus reported walking time 2) Collected water volume versus walking time 14

15 Results 1 5

16 Measured distance to water source (meters) Results: (1) Walking time and measured distance Simple Linear Regression R 2 =0.15 Limited to: Endline data (with water source coordinates) Households reporting using the funded water point Measured distances <1,000 m n=2,643 from 7 countries One-way reported walking time (minutes) 16 Reported one-way walking time (min)

17 Results: (1) Walking time and measured distance Multiple Linear Regression When adjusted for country, Distance increased with increased walking time Estimate: 7.9 meters per minute increase in reported walking time (p<0.001, R 2 =0.22) Non-significant variables: Source type Season of data collection (wet or dry) 17

18 Measured distance to water source (meters) Results: (1) Walking time and measured distance Instead of thinking about this as continuous data 18 One-way reported walking time (minutes)

19 Measured distance to water source (meters) Results: (1) Walking time and measured distance Divided into time increments <5 min >45 19 One-way reported walking time (minutes)

20 Measured distance to water source (meters) Results: (1) Walking time and measured distance Divided into time increments Analysis of variance (ANOVA) p<0.001 <5 min >45 20 One-way reported walking time (minutes)

21 Measured distance to water source (meters) Results: (1) Walking time and measured distance Divided into time increments Analysis of variance (ANOVA) p<0.001 Tukey multiple comparisons of means, each was significant (p<0.05) except the final two (p=0.13) <5 min >45 21 One-way reported walking time (minutes)

22 Measured distance to water source (meters) Results: (1) Walking time and measured distance Distance was significantly greater for those reporting walking over 30 minutes round-trip versus under 30 minutes. Under 30 min round-trip (n=2,132) Over 30 min round-trip (n=511) 172 meters 383 meters Wilcoxon rank sum (p<0.001) 22 Under 15 min one-way walking Over 15 min one-way walking

23 Results: (2) Walking time and reported volume collected Multiple Linear Regression Controlling for source type, queueing, season, and country n=16,142 from 10 countries Households reported collecting less water per person as walking time increased 23

24 2 4 Discussion

25 Maybe, People do sometimes, have a sense of there s near vs. a far, super long important vs. short message that we feel like calling Walking out longer in blue. does mean collecting less water Supplementary text is likes to be below. However 25

26 Limitations [Future work?] Path distance is not the same as straight-line distance Topography was not considered Errors and uncertainty in coordinate measurements 26

27 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) 27

28 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) But, distance was greater with increasing reported time 28

29 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) But, distance was greater with increasing reported time Closer sources are beneficial for collecting more water 29

30 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) But, distance was greater with increasing reported time Closer sources are beneficial for collecting more water This was true when looking across many country contexts 30

31 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) But, distance was greater with increasing reported time Closer sources are beneficial for collecting more water This was true when looking across many country contexts Perfect? No 7.9 meters per minute 31

32 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) But, distance was greater with increasing reported time Closer sources are beneficial for collecting more water This was true when looking across many country contexts Perfect? No 7.9 meters per minute It appears that people overestimate collection time, which would under-estimate levels of Basic Service 32

33 Implications Reported time is not a great predictor of linear distance (R 2 =0.22) But, distance was greater with increasing reported time Closer sources are beneficial for collecting more water This was true when looking across many country contexts Perfect? No 7.9 meters per minute It appears that people overestimate collection time, which would under-estimate levels of Basic Service 33 From a practical data-collection standpoint, it is reasonable for a 12-quesiton survey to establish a measure of access that can be simply and consistently measured globally

34 Thank you! Implementing partners Survey respondents Anna Murray 34

35 Difference between measured distance and calculated distance (meters) Results: (1) Walking time and measured distance Walking rate of 62.5 m/min (Ho et al, 2014) [1 km in 16 min or 1 mile in 25.7 minutes] Over-estimated distance (based on time) If you reported walking 10 min one-way, we would assume you walk 625 meters. Measured distance was 125 meters Difference = +500 meters x *let s remember this is not path distance! Under-estimated <5 min >30 35 One-way reported walking time (minutes)