Experimental Design Details
We will offer access to insurance to a random sample of women of child-bearing age in and around
Dandora, and use randomization in prices to determine the impact of the insurance and the health
center. Insurance will be offered during a baseline interview. At the endline, height-for-age and
weight-for-age measures of child health along with other basic indicators will be collected in addition
to a survey.
I will now describe the voucher distribution and demand elicitation procedure. The vouchers are
insurance contracts: respondents who receive a voucher will pay a 20 - 40 percent deposit within a
week of the survey, and the rest of the cost will be deducted from the face value of the voucher. The
deposit is a premium, and the price of a birth (normal or cesarean) less the remaining face value of
the voucher is a co-pay. We want to see how these respondents value the insurance contracts
presented to them. However, if we simply presented them with a fixed, take-it-or-leave-it price and
asked them to tell us whether they wanted to buy or not, we would only learn whether or not the
contract is acceptable at that price, not what the respondent's actual value is for the contract; we
would then have to make a variety of unrealistic statistical assumptions, such as, for example, that
the unobserved component of the respondent's value is normally distributed. So we want the
respondent to make us an "offer" for a contract with a given face value and deposit. Suppose we
said, "We're going to ask you to make us an offer for this voucher. The voucher has a face value of
KES X and requires a deposit of Y percent of your offer. Whatever you answer will be the price, and
KES X and requires a deposit of Y percent of your offer. Whatever you answer will be the price, and
you have to pay the deposit within a week by mPesa (a very popular mobile money program offered
by Safaricom)." The respondent has a best strategy of answering zero and paying nothing: this is an
even worse demand elicitation procedure, since it gives respondents a clear incentive to understate
their values. In situations like this, economists instead use the Becker-deGroot-Marschak (BDM)
demand elicitation method. It recognizes that when the price paid is out of the respondent's control -
-- as with the take-it-or-leave-it prices --- they behave in a fashion consistent with their true values,
but we want them to report a value, as in the pay-as-reported demand elicitation method that
performs so poorly. In short, BDM works like this: "I have this voucher for KES X that requires a Y
percent deposit. I am going to ask you for an offer, and then I am going to ask you draw a price out
of this bag. If the price is above your offer, you do not get the voucher. If the price is below your
offer, you can buy the voucher at that price. You have to pay a deposit of Y percent of the price
today, and the rest will be deducted from the face value of the voucher. So you will never pay more
than what you offer, and you can end up paying significantly less." The intuition is that if I
deliberately understate my value, I can only lose in the scenario when the price drawn is between
my stated offer and my value, so I lose when it would have been profitable to win; similarly, if I
deliberately overstate my value, I might win in the scenario when the price drawn is between my
stated offer and my value, so I win when I would have preferred to lose. This gives participants a
weakly dominant strategy to set their offer equal to their true value. The face value will be randomly
selected from $30, $50, $100, $150, $200, and $300. For reference, the price of a normal birth at
the clinic is $50, and the price of a cesarian is $300, so that we are offering a range of different risk
levels. The deposit will be randomly selected from 20, 30, or 40 percent. For statistical reasons,
variation in the deposit tells us more about the respondent's risk preferences than varying the value
value, but for economic reasons including full insurance and some under-insurance even for a
normal birth provides information about how various insurance schemes would be received by the
population.
The BDM procedure has a few consequences to mention. First, some people will not get a voucher
despite reporting a high offer, while others will get a voucher despite making a low offer. This is the
experimental variation that we want. The strategy is that winning a voucher will push people who
are "on the fence" about going to the new hospital into going to the hospital, and they can be
compared with people of similar observables and offers, but who did not get the voucher. This is
similar to a standard randomized controlled trial, where some subjects get a treatment and others do
not. The exact statistical methodology is called an instrumental variables regression, or two-stageleast-
squares: we use controlled variation in the likelihood of using the hospital to predict hospital
utilization, and then infer hospital impact from utilization. Second, we cannot deviate from the BDM
procedure ex post and provide vouchers even if the reported offer was below the randomly drawn
price. This undermines the demand elicitation procedure because people might reveal to neighbors
or relations that we sell the voucher afterwards regardless of the outcome; everyone then also has a
weakly dominant strategy to report a price of zero, observe the outcome of the price randomization,
and then buy if the price is favorable.
Deviating from the BDM procedure and selling the voucher ex
post at the randomly drawn price is also not in standard experimental practice in economics:
misleading participants or misrepresenting experiments disqualifies research at most journals.
The reason is that it encourages participants to "meta-reason" about the
interaction and undermines their trust in experimenters in general. Thus, instead of measuring how
health uncertainty determines willingness-to-pay for insurance, we are measuring the subject's
uncertainty about our intentions and what the outcome of the experiment is. Economics as a
discipline tries to avoid introducing this kind of meta-uncertainty into subject pools since it has
negative consequences for all economics experiments. During a trip to Kenya, we piloted this kind
of procedure for simpler goods like bags of sugar and tea, and participants understood relatively
quickly how it worked, especially after doing one or two practice rounds, which are part of the
protocol.
In addition to the BDM procedure, we have a simple procedure for eliciting beliefs about the risk of a
cesarian and the likelihood of becoming pregnant. The procedure involves a sheet of paper with two
boxes and ten beans or other counters. One box is labelled "Cesarian Section Birth" and the other
is labelled "Normal Birth". The enumerator begins by saying, "If you think you will have a normal
birth for sure, place all the beans in the Normal Birth box", and does so. Then she says, "If you think
you will have a Cesarian section birth for sure, place all the beans in the Cesarian Section Birth
box," and does so. Then she says, "If you think a normal birth and a Cesarian section birth are
equally likely, put the same number of beans in each box," and does so. Then she says, "So now,
move the beans back and forth between the two boxes until you think it reflects the chance you need
a Cesarian section." This is also done where normal birth and Cesarian section birth are replaced
with the likelihood of becoming pregnant. This helps us measure the subjective beliefs of the
subjects about the likelihood they become pregnant or require much more expensive care.
In the absence of the vouchers, care at the Health Center requires payment. There are free
government facilities, but these are commonly known to be low quality and stressful places to give
birth. There are several facilities nearby that offer better services for prices comparable to what the
Health Center is charging. The vouchers will therefore deduct from the price of care that households
must pay, but will mostly not fully reimburse the household for care received.
I will now describe follow-up procedures. Women who receive a voucher and deliver at the Health
Center will be indicated in bills received by the hospital, but we will have no indication whether a
woman who does not receive a voucher or who receives the voucher but does not deliver at the
Health Center gave birth. We will return to survey areas at the endline and contact parents to
schedule a survey (we will record GPS coordinates of the place of the initial interview and whether
this is the woman's current residence or place of business). The endline survey will be identical to
the baseline survey, where the current questions about all previous births are restricted to births
since the baseline, and other questions whose answers do not change over time are dropped.