To test whether differences in intrahousehold discount factors results in inefficient savings, sample couples were given the opportunity to open up to three bank accounts at the Family Bank in Kenya: a joint account, an individual account for the husband, and/or an individual account for the wife. Before the offer, each account was randomly assigned to qualify for one of four temporary, six-month interest rates. An individual account could bear 0, 2, 6, or 10 percent 6-month yields and joint accounts could bear 2, 6 or 10 percent 6-month interest rates. The interest rates were purposely chosen to exceed market rates by a large margin, with the hope that they would encourage account use and increase savings. After the six-month interest rate expired, researchers measured take-up, account use, savings behavior, and economic impacts for individual and joint account holders. Researchers measured the same outcomes again after another two and a half years to understand the long-term effects of the interest rate subsidies.
In order to test whether the ability to hide savings was an important driver of individual account use, 50 percent of participating couples were randomly selected for an "extra statements" offer. If a selected couple decided to open an individual account for (without loss of generality) spouse A , the enumerator processing the couple’s paperwork asked if the spouses would consent to allow spouse B to receive extra statement cards. The cards, if presented by spouse B at the bank, entitled him or her to learn the current balance of spouse A ’s account. These cards were only valid for 6 months, and were not given to couples unless both spouses gave their consent.