Download StudyGeneral

Study Overview

Willingness to pay for improved crop storage bags among smallholder farmers in Western Kenya: comparing demand generation effectiveness of text, audio, and video messages
Study is 3ie funded:
Study ID:
Initial Registration Date:
Last Update Date:
Study Status:
Purdue Improved Crop Storage (PICS) bags, developed at Purdue University, are inexpensive plastic grain-storage bags which prevent pest damage during crop storage, with the aim to increase the income of farming families by reducing post-harvest losses. The PICS bag was introduced to the Kenyan market in 2013 and is the current Kenyan market leader for this technology; however, market penetration remains at less than 1% of the total potential market for grain storage in Kenya. This study aims to compare the effectiveness of different media at generating interest in the PICS bags among smallholder farmers in Western Kenya, most of whom have not been previously exposed to the PICS bags. Individual farmers are randomly given a short textual, audio, or video informational message about the PICS bags. They are then asked for their willingness to pay for a bag using the Becker-DeGroot-Marschak method, yielding demand curves for the bag for each of the different media types. These findings can inform PICS demand generation activities, and also provide broader learning on increasing adoption of agricultural technologies among smallholder farmers in the region.
Agriculture and Rural Development
Information and Communications Technology
Private Sector Development
Additional Keywords:
post-harvest crop storage, demand generation, willingness to pay
Secondary ID Number(s):
Bill & Melinda Gates Foundation Grant Investment ID: OPP1129552

Principal Investigator(s)

Name of First PI:
Daniel Stein
Name of Second PI:
Patricia Pina

Study Sponsor

Bill & Melinda Gates Foundation
Study Sponsor Location:
United States

Research Partner

Name of Partner Institution:
Purdue University (Purdue Improved Crop Storage (PICS) project)
Type of Organization:
Research institute/University
United States

Intervention Overview

Purdue Improved Crop Storage (PICS) bags, developed at Purdue University, are inexpensive plastic grain-storage bags which prevent pest damage during crop storage. PICS project staff are working with local manufacturers and entrepreneurs throughout West, Central, and East Africa to produce and distribute the bags. In Kenya, PICS bags were introduced in November 2013 in partnership with Bell Industries Limited. For this evaluation, farmers are given one of three different informational messages about the bags during the survey: 1) a textual message, adapted from one of Bell Industries’ fliers; 2) an audio message, adapted from a short radio ad previously produced by PICS; and 3) a video message, previously produced by PICS. The message is shown or played on an Android phone provided by the enumerator. The survey for most farmers takes place at a scheduled farmer group meeting, typically at another farmer’s home, or at the interviewed farmer’s own home. Note that the intervention timeline refers to the start and end dates of the survey, during which messages are shown to the respondents during each individual survey.
Theory of Change:
Multiple Treatment Arms Evaluated?

Implementing Agency

Name of Organization:
Type of Organization:
NGO (International)

Program Funder

Name of Organization:
Bill & Melinda Gates Foundation
Type of Organization:
NGO (International)

Intervention Timing

Intervention or Program Started at time of Registration?
Start Date:
End Date:
Evaluation Method

Evaluation Method Overview

Primary (or First) Evaluation Method:
Randomized control trial
Other (not Listed) Method:
Additional Evaluation Method (If Any):
Other (specify)
Other (not Listed) Method:
Willingness to pay (Becker-DeGroot-Marschak method)

Method Details

Details of Evaluation Approach:
This study includes participating farmers in smallholder farmer loan groups in areas surrounding Kitale and Eldoret in Western Kenya. Farmers are randomly assigned to be given either a textual, audio, or video informational message about the PICS bag. Immediately after exposure to the message, farmers participate in a Becker-DeGroot-Marschak willingness to pay exercise, where farmers are asked for the highest price they would be willing to pay for the bag (they are told that the market price varies and goes up to 300 Kenyan Shillings). After offering a price, farmers draw a price at random from a set of envelopes: if the farmer’s price is equal to or higher than the drawn price, they win the bag and must pay the drawn price; otherwise, they do not win the bag. Because of the potentially high cost of the bag, farmers are offered the option of paying in one week’s time. Farmers are also asked how likely they are to recommend the bag to friends and family on a scale from zero to ten, as another measure of how interested they are in the product.
Outcomes (Endpoints):
Demand curve for PICS bag; Offered price for PICS bag; Willingness to pay X Kenyan Shillings or more for PICS bag (at 200, 210, 250); Self-reported likelihood to recommend bag to friends and family
Unit of Analysis:
Individual farmer
Farmers receiving textual, audio, and video informational messages will differ in the maximum price they are willing to pay for PICS bags. Farmers receiving textual, audio, and video informational messages will differ in their self-reported likelihood to recommend PICS bags to friends and family.
Unit of Intervention or Assignment:
Individual farmer
Number of Clusters in Sample:
Number of Individuals in Sample:
Size of Treatment, Control, or Comparison Subsamples:
Farmers receiving textual message: 217, Audio: 251, Video: 256

Supplementary Files

Analysis Plan:
Other Documents:

Outcomes Data

IDinsight is administering one round of primary data collection for this study, conducted in areas surrounding Kitale and Eldoret in Western Kenya in March-April 2016. Individual farmers who participate in farmer loan groups will be individually surveyed at either loan group meetings or at their households.
Data Already Collected?
Data Previously Used?
Data Access:
Not restricted - access with no requirements or minimal requirements (e.g. web registration)
Data Obtained by the Study Researchers?
Data Approval Process:
Approval Status:

Treatment Assignment Data

Participation or Assignment Information:
Data Obtained by the Study Researchers?
Data Previously Used?
Data Access:
Data Obtained by the Study Researchers?
Data Approval Process:
Approval Status:

Data Analysis

Data Analysis Status:

Study Materials

Upload Study Materials:

Registration Category

Registration Category:
Prospective, Category 3: Data for measuring impacts have been obtained/collected by the research team but analysis for this evaluation has not started

Completion Overview

Intervention Completion Date:
Data Collection Completion Date:
Unit of Analysis:
Clusters in Final Sample:
Total Observations in Final Sample:
Size of Treatment, Control, or Comparison Subsamples:


Preliminary Report:
Preliminary Report URL:
Summary of Findings:
Paper Summary:
Paper Citation:

Data Availability

Data Availability (Primary Data):
Date of Data Availability:
Data URL or Contact:
Access procedure:

Other Materials

Survey Instrument Links or Contact:
Program Files:
Program Files Links or Contact:
External Link:
External Link Description:
Description of Changes:

Study Stopped