Does Peer Use Influence Adoption of Efficient Cookstoves? Evidence From a Randomized Controlled Trial in Uganda

Figures & data

Table 1a. Summary statistics of matched early and late buyers and their neighbors

General summary statistics	N	%
Experimental sample—early and late buyers—who took survey^a	159	100
Count of female participants among experimental sample	131	82
Neighbors of early and late buyers who took survey	763	100
Neighbors surveyed who already own Envirofit	95	13
Neighbors excluding those who already own Envirofit	668	100
Neighbors surveyed listed frequent communication with early or late buyer	353	53
Total neighbors who are non-recommended by early or late buyer^b	146	19
Of whom already own stoves	7	5
Of whom listed frequent communication with early or late buyer	41	28
Total recommended neighbors by early or late buyer neighbors	617	92
Of whom already own stoves	88	14
Of whom listed frequent communication with early or late buyer	312	50
Envirofit stove sales to neighbors
Total Neighbors who purchase a stove	61	100
Of whom are neighbors of early buyers	21	34
Of whom are neighbors of late buyers	40	66
Other community members who purchase a stove^c	51	N.A.
Neighbors excluding those who already own stoves	N	Mean	SD	Median
Average geographic distance between neighbors^d(kilometers)	641	0.20	0.32	0.13
of which distance from neighbors of early buyers	303	0.20	0.13	0.28
of which distance from neighbors of late buyers	361	0.25	0.13	0.36
	Early buyers		Late buyers
Neighbors only who have not yet purchased an Envirofit	N	%	N	%
Total sample	304	100	364	100
Neighbor attended original sales meeting	27	9	34	9
Reciprocated friendships^e	160	53	193	53

Notes: ^aOne late buyer and one early buyer survey are missing a survey. Despite these two surveys being missing, we have survey data from their neighbors. This accounts for the discrepancy between 312 total recommended neighbors who list early or late buyer in general statistics and 308 with a matched survey in later analysis. ^b19% represents a percentage of the total 763 sample. ^cNotably, it is feasible that among the 412 original buyers in the 14 parishes, additional neighbors own an Envirofit from the previous sales study. Thus, the total sample of non-recommended neighbors close to a neighbor is unknown. ^dThe variable average geographic distance is topcoded at 1.5 kilometers.^eReciprocated friendships represent neighbors who also listed closest early or late buyer as close friend.

Table 1b. Summary statistics related to communication and shared activities between neighbors

Neighbors who have not purchased an Envirofit	Total sample		Early buyers	Late buyers
	N	%	%	%
Total sample	668	100	100	100
Neighbors who list experimental early or late buyer	353	53	53	53
Frequency of contact between neighbors	355	100	100	100
Daily	226	64	63	64
Three times a week	70	20	21	19
Once a week	44	12	12	12
Twice a month	3	1	2	0
Monthly	7	2	1	3
Less than once a month	5	1	1	2
Last reported contact between neighbors	354	100	100	100
Today	147	42	45	39
Two to six days ago	174	49	47	51
A week ago	14	4	3	5
Two weeks ago	8	2	2	3
A month ago	11	3	3	3
Type of activities reported reported by neighbors*	358	100	100	100
Attend family events together**	70	20	24	16
Farm together	82	23	22	24
Attend church together	118	33	35	31
Are part of same ROSCA^a*	66	18	22	16
Are part of same Kwesika group that assists with burials	77	22	21	22
Report no shared activities	58	16	17	16
Participant consults experimental neighbor with problems	315	89	89	89
If yes, how frequently do you consult experimental neighbor
All the time	51	16	15	17
Most of the time	140	44	43	46
Some of the time	95	30	33	28
Not very frequently	29	9	8	10
	N	Mean	Mean	Mean
Index of social closeness^b	354	12	12	12
Standardized index of social closeness^b	354	0.01	0.17	−0.12

Notes: The sample includes both recommended and non-recommended buyers, but drops 95 neighbors who previously purchased a stove in an earlier study. The data presented is based on survey responses from neighbors of the experimental sample. ^aROSCA is the abbreviation for Rotating Savings and Credit Association. ^bThe “Index of social closeness” is a combination of the variables “Frequency of contact between neighbors,” “Last reported contact between neighbors,” the count of “Type of activities reported by neighbors,” and “Yes participant consults with the experimental neighbor if had a problem.” The “Index of social closeness” has been constructed such that all four variables are coded so 0 indicates least socially close. As a result the count variable of the four measures of social closeness ranges from 0–14 with zero being the least close and 14 being highest on the social closeness index. For regression analysis the “Standardized index of social closeness” has been constructed such that each of the four variables has a mean of zero and a standard deviation of 1. Statistical significance from t-tests indicated by *p < .10, **p < .05, ***p < .01.

Table 1c. Summary Statistics of neighbors’ knowledge and experience with Envirofit cookstove

	Total sample		Early buyers	Late buyers
All neighbors who have not yet purchased a stove	N	%	%	%
Total sample	668	100	100	100
Knowledge about the Envirofit cookstove
Participant knows about the stove,***	172	26	22	29
Of whom, knows about stove from the experiment***	99	57	68	50
Participant knows one person who owns stove***	267	40	43	38
Participant knows at least two people who own stove***	95	14	19	10
Participant seen one person cook with stove***	167	25	31	20
Participant seen more than one person use stove***	51	8	9	6
Participant knows focal point person	433	65	65	65
Participant knows focal point person owns stove	121	28	27	29
Participant seen focal point person cook with stove	29	24	28	21
Other neighbor(s) bought Envirofit**
1 other	183	27	26	29
2 others	38	6	6	5
3 others	23	3	2	5
Opinions about the Envirofit cookstove
Participant selects Envirofit is better for your health**	153	23	20	26
Participant selects Envirofit is easier to use*	141	21	18	23
Participant selects Envirofit uses less fuel*	150	23	20	25
Participant heard good things about Envirofit stove*	144	22	19	24
Participant heard bad things about Envirofit stove**	25	4	2	5

Notes: For the following variables:“Participant selects the Envirofit is better for your health;” “Participant selects the Envirofit is easier to use;” “Participant selects the Envirofit uses less fuel (compared to three stone fire)”; respondents were asked to rank the Envirofit from 1 to 10. Here 1 represents the Envirofit was strongly better than a three stone fire. These variables have been constructed as dummy variables assigned a 1 if the ranking given was a 1 or 2 (indicating a strong preference for the Envirofit) or a 0 for rankings 3 through 10. Other neighbor(s) bought Envirofit- represents other neighbors (those not verbally mentioned as neighbors, but who lived in close geographic proximity) that purchased an Envirofit at the same time as the early or late buyer neighbor. In total, 95 additional buyers are part of the Other neighbor(s) who bought Envirofit group. Statistical significance from t-tests indicated by *p < .10, **p < .05, ***p < .01.

Table 1d. Summary statistics of sociodemographics for neighbors related to cooking

	Total sample		Early buyers	Late buyers
	Mean	Median	Mean	Mean
Average age	25	30	25	26
No. of people who ate lunch yesterday^a	13	12	13	13
Typical no. of people who eat lunch^a	13	13	13	13
	N	%	%	%
Wood is the fuel used for cooking***	664	94	97	92
The largest meal cooked in the household	664	100	100	100
Breakfast	7	1	1	1
Lunch	84	13	9	16
Dinner	435	66	66	65
We never cook at our house	138	21	24	18
Neighbors gather wood last week or month	662	18	19	19
Yes, neighbor reports earning income***	664	90	91	89
Of which is earned in cash only	219	36	32	40
Of which is earned in-kind only	37	6	8	5
Of which is earned in both cash and in-kind	345	57	60	55
Of which is not paid	3	0.5	1	0
Yes, neighbor has a television	664	8	9	8
Yes, neighbor has a radio	664	88	88	87
Yes, neighbor has a cell phone	664	70	68	72
Yes, neighbor owns cows	664	21	21	21
Count of four assets owned	664	100	100	100
Of which 0 assets owned	46	7	7	7
Of which 1 asset owned	163	25	26	23
Of which 2 assets owned	317	48	46	49
Of which 3 assets owned	110	17	17	16
Of which 4 assets owned	28	4	4	5

Notes: ^aBoth the average number of people who ate lunch yesterday and eat lunch on a typical basis includes only those who report a positive number. Statistical significance from t-tests indicated by *p < .10, **p < .05, ***p < .01.

Table 2. Summary statistics for neighbors who have not purchased an Envirofit

	Total sample		Early buyers	Late buyers
	N	%	%	%
Interested in lump sum payment***
Yes	157	24	21	26
Maybe	134	20	19	21
No	373	56	60	53
Interested in pay half now and half in 4 weeks*
Yes	197	30	28	32
Maybe	208	31	33	30
No	259	39	28	38
Purchased the Envirofit**	61	9	7	11
Of whom paid half now and half in 4 weeks	52	85	85	85
Of whom paid one lump sum payment	9	15	14	15

Notes: Statistical significance from t-tests indicated by *p < .10, **p < .05, ***p < .01.

Table 3. The effect of a neighbor's ownership of an Envirofit on familiarity and opinions about the Envirofit

	(A)	(A)	(B)	(B)
Neighbor of early buyer	0.17*** (0.07)	0.20*** (0.06)	0.11* (0.06)	0.13*** (0.05)
Asset count	0.01 (0.03)	0.01 (0.03)	0.12 (0.03)	0.12 (0.03)
Household never cooks	−0.01 (0.07)	−0.05 (0.06)	0.05 (0.06)	−0.01 (0.06)
Other neighbor(s) bought Envirofit		0.13*** (0.04)		0.13*** (0.05)
Knows focal person		0.55*** (0.06)		0.42*** (0.06)
Constant	1.09*** (0.15)	0.86*** (0.16)	1.02*** (0.15)	0.82*** (0.16)
Parish fixed effects	Yes	Yes	Yes	Yes
Observations	658	658	658	658
R-squared	0.11	0.21	0.16	0.24

Notes: The dependent varaible for specification A is no. of people neighbor knows who own Envirofit; Specification B is no. of people neighbor has seen cook with Envirofit. Other neighbor(s) bought Envirofit represents other neighbors (those not verbally mentioned as neighbors, but who lived in close geographic proximity) that purchased an Envirofit at the same time as the early or late buyer neighbor. In total, 95 additional buyers are part of the Other neighbor(s) who bought Envirofit group. Standard errors, clustered by shared early or late buyer, in parentheses. Statistical significance indicated by *p < .10, **p < .05, ***p < .01.

Table 4. The effect of a neighbor's ownership of an Envirofit on familiarity and opinions about the Envirofit.

	A	B	C
	(Improves health)	(Easier to use)	(Uses less fuel)
Neighbor of early buyer	−0.06* (0.04)	−0.04 (0.04)	−0.05 (0.04)
Asset count	0.02 (0.02)	0.01 (0.02)	0.02 (0.02)
Household never cooks	−0.05 (0.04)	−0.01 (0.04)	−0.15 (0.04)
Other neighbor(s) bought Envirofit	0.02 (0.03)	0.01 (0.03)	0.02 (0.03)
Knows focal person owns Envirofit	0.22*** (0.06)	0.17*** (0.06)	0.19*** (0.06)
Constant	0.31*** (0.09)	0.33*** (0.09)	0.31*** (0.09)
Parish fixed effects	Yes	Yes	Yes
Observations	658	658	658
R-squared	0.09	0.07	0.08

Notes: The dependent variable for specification A is neighbor believes Envirofit improves health; specification B is neighbor believes Envirofit is easier to use; specification C is neighbor believes Envirofit uses less fuel. Other neighbor(s) bought Envirofit represents other neighbors (those not verbally mentioned as neighbors, but who lived in close geographic proximity) that purchased an Envirofit at the same time as the early or late buyer neighbor. In total, 95 additional buyers are part of the Other neighbor(s) who bought Envirofit group. Standard errors, clustered by shared early or late buyer, in parentheses. Statistical significance indicated by *p < .10, **p < .05, ***p < .01.

Table 5. Predicting purchase of the Envirofit

	Purchase	Purchase	Purchase	Purchase
	(1)	(2)	(3)	(4)
Neighbor of early buyer	−0.03 (0.02)	−0.02 (0.03)	−0.01 (0.03)	−0.01 (0.03)
Asset count	0.04*** (0.01)	0.04* (0.02)	0.04* (0.02)	0.04* (0.02)
Household never cooks	0.05* (0.03)	0.03 (0.04)	0.04 (0.04)	0.04 (0.04)
Other neighbor(s) are early or late buyer	0.01 (0.02)		0.02 (0.03)
Knows focal person owns Envirofit	−0.01 (0.03)		0.03 (0.05)
Social closeness index		0.01 (0.01)		0.01 (0.01)
Neighbor of early buyer * Social closeness		0.01 (0.01)		0.01 (0.01)
Constant	−0.03 (0.04)	−0.06 (0.04)	−0.08 (0.05)	−0.06 (0.04)
Parish fixed effects	Yes	Yes	Yes	Yes
Observations	658	348	308	308
R-squared	0.08	0.12	0.12	0.13

Notes: Specifications 1-2 use the total sample and specifications 3-4 use the subsample of symmetric strong linked neighbors with experimental early/late buyers. To measure social closeness we created an index of self-reported frequency of communication between the respondent and the experimental neighbor, number of shared activities with the experimental neighbor, and whether the respondent would solicit advice from the experimental neighbor. For each of the four variables we create a standardized score so that each variable has a mean of 0 and standard deviation of 1. Further, the sample size drops for the social closeness variable because enumerators generally recorded data only for the subset of households who selected the early or late buyer as someone they speak to frequently. Standard errors, clustered by shared early or late buyer, in parentheses. Statistical significance indicated by *p < .10, **p < .05, ***p < .01.