Validation of an Automated Wearable Camera-Based Image-Assisted Recall Method and the 24-h Recall Method for Assessing Women's Time Allocation in a Nutritionally Vulnerable Population: The Case of Rural Uganda

Abstract

Accurate data are essential for investigating relationships between maternal time-use patterns and nutritional outcomes. The 24 h recall (24HR) has traditionally been used to collect time-use data, however, automated wearable cameras (AWCs) with an image-assisted recall (IAR) may reduce recall bias. This study aimed to evaluate their concurrent criterion validity for assessing women's time use in rural Eastern Ugandan. Women's (n = 211) time allocations estimated via the AWC-IAR and 24HR methods were compared with direct observation (criterion method) using the Bland-Altman limits of agreement (LOA) method of analysis and Cronbach's coefficient alpha (time allocation) or Cohen's κ (concurrent activities). Systematic bias varied from 1 min (domestic chores) to 226 min (caregiving) for 24HR and 1 min (own production) to 109 min (socializing) for AWC-IAR. The LOAs were within 2 h for employment, own production, and self-care for 24HR and AWC-IAR but exceeded 11 h (24HR) and 9 h (AWC-IAR) for caregiving and socializing. The LOAs were within four concurrent activities for 24HR (-1.1 to 3.7) and AWC-IAR (-3.2 to 3.2). Cronbach's alpha for time allocation ranged from 0.1728 (socializing) to 0.8056 (own production) for 24HR and 0.2270 (socializing) to 0.7938 (own production) for AWC-IAR. For assessing women's time allocations at the population level, the 24HR and AWC-IAR methods are accurate and reliable for employment, own production, and domestic chores but poor for caregiving and socializing. The results of this study suggest the need to revisit previously published research investigating the associations between women's time allocations and nutrition outcomes.

Keywords: care practices; maternal time; measurement error; methodology; time use; validation studies; wearable camera.

Figure 1

Study population. OBS, observation; IAR, image-assisted recall.

Figure 2

Bland–Altman (BA) plots of time allocation difference versus the mean of observation (OBS) and 24 h recall (24HR) or image assisted recall (IAR). (a) BA plot for employment and related activities (MD1), OBS and 24HR, (b) BA plot for employment and related activities (MD1), OBS and IAR, (c) BA plot for production of goods for own final use (MD2), OBS and 24HR and (d) BA plot for production of goods for own final use (MD2), OBS and IAR. (e) BA plot for unpaid domestic services for household and family members (MD3), OBS and 24HR, (f) BA plot for unpaid domestic services for household and family members (MD3), OBS and IAR, (g) BA plot for unpaid caregiving services for household and family members (MD4), OBS and 24HR, and (h) BA plot for unpaid caregiving services for household and family members (MD4), OBS and IAR, (i) BA plot for socializing and communication, community participation, and religious practice (MD7), OBS and 24HR, (j) BA plot for socializing and communication, community participation, and religious practice (MD7), OBS and IAR, (k) BA plot for culture, leisure, mass media, and sports practices (MD8), OBS and 24HR, and (l) BA plot for culture, leisure, mass media, and sports practices (MD8), OBS and IAR, (m) BA plot for self-care and maintenance (MD9), OBS and 24HR, and (n) BA plot for self-care and maintenance (MD9), OBS and AR. The dotted line is the mean difference (bias), the long-dashed lines are +/− 2SD limits of agreement (LOA). A bias > 0 indicates that 24HR or IAR underestimates time allocation.

Figure 2

Bland–Altman (BA) plots of time allocation difference versus the mean of observation (OBS) and 24 h recall (24HR) or image assisted recall (IAR). (a) BA plot for employment and related activities (MD1), OBS and 24HR, (b) BA plot for employment and related activities (MD1), OBS and IAR, (c) BA plot for production of goods for own final use (MD2), OBS and 24HR and (d) BA plot for production of goods for own final use (MD2), OBS and IAR. (e) BA plot for unpaid domestic services for household and family members (MD3), OBS and 24HR, (f) BA plot for unpaid domestic services for household and family members (MD3), OBS and IAR, (g) BA plot for unpaid caregiving services for household and family members (MD4), OBS and 24HR, and (h) BA plot for unpaid caregiving services for household and family members (MD4), OBS and IAR, (i) BA plot for socializing and communication, community participation, and religious practice (MD7), OBS and 24HR, (j) BA plot for socializing and communication, community participation, and religious practice (MD7), OBS and IAR, (k) BA plot for culture, leisure, mass media, and sports practices (MD8), OBS and 24HR, and (l) BA plot for culture, leisure, mass media, and sports practices (MD8), OBS and IAR, (m) BA plot for self-care and maintenance (MD9), OBS and 24HR, and (n) BA plot for self-care and maintenance (MD9), OBS and AR. The dotted line is the mean difference (bias), the long-dashed lines are +/− 2SD limits of agreement (LOA). A bias > 0 indicates that 24HR or IAR underestimates time allocation.

Figure 2

Bland–Altman (BA) plots of time allocation difference versus the mean of observation (OBS) and 24 h recall (24HR) or image assisted recall (IAR). (a) BA plot for employment and related activities (MD1), OBS and 24HR, (b) BA plot for employment and related activities (MD1), OBS and IAR, (c) BA plot for production of goods for own final use (MD2), OBS and 24HR and (d) BA plot for production of goods for own final use (MD2), OBS and IAR. (e) BA plot for unpaid domestic services for household and family members (MD3), OBS and 24HR, (f) BA plot for unpaid domestic services for household and family members (MD3), OBS and IAR, (g) BA plot for unpaid caregiving services for household and family members (MD4), OBS and 24HR, and (h) BA plot for unpaid caregiving services for household and family members (MD4), OBS and IAR, (i) BA plot for socializing and communication, community participation, and religious practice (MD7), OBS and 24HR, (j) BA plot for socializing and communication, community participation, and religious practice (MD7), OBS and IAR, (k) BA plot for culture, leisure, mass media, and sports practices (MD8), OBS and 24HR, and (l) BA plot for culture, leisure, mass media, and sports practices (MD8), OBS and IAR, (m) BA plot for self-care and maintenance (MD9), OBS and 24HR, and (n) BA plot for self-care and maintenance (MD9), OBS and AR. The dotted line is the mean difference (bias), the long-dashed lines are +/− 2SD limits of agreement (LOA). A bias > 0 indicates that 24HR or IAR underestimates time allocation.

Figure 3

Bland–Altman (BA) plots of time allocation difference versus the mean of observation (OBS) and 24 h recall (24HR) or image-assisted recall (IAR). (a) BA plot for concurrent activities-OBS and 24HR, (b) BA plot for concurrent activities, OBS and IAR. The dotted line is the mean difference (bias), the long-dashed lines are +/− 2 SD limits of agreement (LOA). A bias > 0 indicates that 24HR or IAR underestimates time allocation. The size of the point corresponds with the number of households.