The Last Meter: Incentivizing Lead Water Service Line Inspections among Hard-to-Reach Populations in Trenton, NJ.

This project studied several interventions designed to encourage addresses to make use of the local lead service line self-inspection program, which allows residents to submit photos of their service lines to have their material identified. Addresses will be assigned to one of the following treatments: an informational treatment consisting of distributed materials explaining the program, or a financial incentive treatment consisting of the same materials, but with the offer of a gift card reward for participating in the program.

Addresses that do not respond to treatment after one month will receive one of the following cross-randomized treatment enhancements to allow us to estimate the costs and impacts of varied treatment intensities to inform policy feasibility at scale in Phase 2: remote outreach via email, SMS, or both requesting them to complete the self-inspection.

2023-01-09

2023-05-29

Participation in lead service line self-inspection program

Inspection participation will be measured as submission of self-inspection service line photos that are of adequate quality to ascertain pipe material between the start of the intervention and the end of the intervention period.

Water service line material

Water service line material, on the private side of the service line, will be determined from professional review of the submitted self-inspection, and grouped by either "contains lead" or "does not contain lead."

This study focuses on the impact of different outreach and engagement methods designed to encourage households to submit a self-inspection of their service lines to help the local utility identify which addresses have lead service lines connecting them to the water system.

Each address in our sample of 9,000 is assigned to one of three roughly equal-sized experimental groups of 3,000 addresses – Treatment 1 (information only), Treatment 2 (information and financial incentive), or Control (no further outreach or incentive). Participating households will submit photos of their service line online, following instructions to ensure they are of sufficient quality for trained staff to identify the service line material.

For Phase 2, after one month, we will randomize all addresses that were assigned to Treatment 1 or 2 but did not respond to the intervention into one of three, equal-sized, cross-randomized, secondary treatments – Secondary Treatment 1 (remote outreach), Secondary Treatment 2 (remote outreach and financial incentive), or Control (no additional treatment).

We will principally examine the difference in uptake between each of these interventions and the control. We will also compare the difference in uptake between different levels of financial incentive to trace demand curves for the program, and will examine the prevalence of lead among respondents at different levels of incentive to assess if households that already know they do not have lead are less likely to participate in the absence of a high incentive.

This study focuses on the impact of different outreach and engagement methods designed to encourage households to submit a self-inspection of their service lines to help the local utility identify which addresses have lead service lines connecting them to the water system.

Each address in our sample of 9,000 is assigned to one of three roughly equal-sized experimental groups of 3,000 addresses – Treatment 1 (information only), Treatment 2 (information and financial incentive), or Control (no further outreach or incentive). Addresses assigned to Treatment 2 will be further randomly assigned to one of four incentive levels: $10, $25, $50, or $100. In Phase 1, each household will receive a door hanger that either only has information about the program, or that offers them one of the described financial incentives. Participating households will go to the website indicated on the door hanger and submit photos of their service line, following instructions to ensure they are of sufficient quality for trained staff to identify the service line material. Households will receive their gift card reward automatically upon verification that their photos are of sufficient quality to have the service line material verified.

For Phase 2, after one month, we will randomize all addresses that were assigned to Treatment 1 or 2 but did not respond to the intervention into one of three, equal-sized, cross-randomized, secondary treatments – Secondary Treatment 1 (remote outreach), Secondary Treatment 2 (remote outreach and financial incentive), or Control (no additional treatment).

We will principally examine the difference in uptake between each of these interventions and the control. We will also compare the difference in uptake between different levels of financial incentive to trace demand curves for the program, and will examine the prevalence of lead among respondents at different levels of incentive to assess if households that already know they do not have lead are less likely to participate in the absence of a high incentive.

Randomized assignment before treatment done in office by a computer

Residential address

No

9,000 residential addresses

9,000 residential addresses

Control: 3,000 residential addresses
Treatment 1 (information only): 3,000 residential addresses
Treatment 2a ($10 incentive): 875 residential addresses
Treatment 2b ($25 incentive): 875 residential addresses
Treatment 2c ($50 incentive): 750 residential addresses
Treatment 2d ($100 incentive): 500 addresses

We are powered to detect a 2.28 percentage point increase in the rate of uptake in the treatment groups for Treatment 1 or Treatment 2 (i.e. an increase of 68 more households participating in the program), with 80% power and alpha 0.05.