Self-Control and Chronic Illness: Theory and Evidence From a Field Experiment

Individuals either diagnosed with or at risk of hypertension were offered commitment contracts or price discount coupons to visit the weekly health clinic called “Hypertension Days” in their village for 3 times in 6 months. Specifically, individuals were randomly assigned into one of the following groups: (1) fixed (standard) commitment contracts without discount, (2) fixed (standard) commitment contracts with discount, (3) flexible (self-designed) commitment contracts without discount, (4) flexible (self-designed) commitment contracts with discount, (5) 50% discount coupons, (6) control group.

A fixed (standard) commitment contract works as follows. Should the respondent decide to sign up, she would be required to pay in advance for all 3 doctor visits (Rs. 60 or Rs. 20 per visit). She would also be asked to pay an additional commitment amount of Rs. 30, which she receives back in equal installments of Rs. 10 each time she visits the doctor. In other words, the respondent pays a total of Rs. 90 up front, and receives Rs. 10 on each of 3 visits.

A flexible (self-designed) commitment contract works similarly, but the respondent would be able to choose the commitment amount beginning with Rs. 0. As above, the respondent receives this committed amount back in 3 equal installments every time she visits the doctor.

2012-08-01

2013-05-31

Primary outcomes: commitment contract take-up; attendance at “Hypertension Days”; blood pressure: Secondary outcomes: diet profile; health status, behavior, knowledge and perceptions; health measurements (body weight, waist circumference, BMI)

The sample selection and randomization works as follows. Since “Hypertension Days” are targeted towards patients with high blood pressure, our study sample consists of individuals above the age of 30 who are either diagnosed with or at risk of hypertension. We follow widely accepted medical guidelines and define hypertensive patients as those with systolic blood pressure above 140 or diastolic blood pressure above 90. To identify hypertensive individuals, a team of enumerators first screened all members of a particular household by measuring their blood pressure using an automatic blood pressure measurement device. If the systolic or diastolic blood pressure reading is above the thresholds previously described, the enumerator immediately invites the individual to participate in the study and to complete the baseline survey. In the event that more than one household member has hypertension, the member with the highest stage of hypertension (stage 1 or stage 2), is selected to take part in the study. Finally, in the event that more than one household member has the same hypertension stage, the member with the highest systolic blood pressure reading is selected to take part in the study. During the same household visit in which the baseline survey is administered, the respondent was offered a commitment contract or price discount coupons to visit the weekly “Hypertension Day” in their village for 3 times in 6 months, as described in the intervention section above. Note that before commencing the study, we conducted a census in all villages in our sample and collected data on household characteristics. We used this census data to randomize all households in the village prior to the enumerators’ visit.

The randomization was conducted in our field office using a computer random number generator.

Individual

No

N/A

1728 individuals

294 individuals are assigned to the control group, while 290 are assigned to receive a 50% price discount on the cost of consultations. Among the remaining individuals, 287 were offered a standard commitment contract (with a fixed commitment amount) without any discounts, 280 were offered a standard commitment contract with a 50% discount. Finally, 283 individuals were offered a self-designed (flexible) commitment contract without discount, and 294 were offered a self-designed commitment contract with a 50% discount.