Food Constraints, Yield Uncertainty and “Ganyu” Labour

Last registered on February 12, 2018


Trial Information

General Information

Food Constraints, Yield Uncertainty and “Ganyu” Labour
Initial registration date
November 21, 2013

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
November 21, 2013, 12:18 PM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
February 12, 2018, 8:34 AM EST

Last updated is the most recent time when changes to the trial's registration were published.


Primary Investigator

Swiss Tropical and Public Health Institute

Other Primary Investigator(s)

PI Affiliation
Tufts University
PI Affiliation
University of Zambia

Additional Trial Information

Start date
End date
Secondary IDs
Small-scale farming continues to be the principal source of nutrition, employment and income for a majority of the population in developing countries. A large literature has documented the frequent absences of small scale farmers from their own field during the cropping season to engage in short-term "ganyu" labor outside of their households. Qualitative evidence suggests that the observed labor supply off-farm is neither planned nor desired by household, but rather a coping strategy employed by financially distressed households to overcome short-term credit constraints. However, research on the relationship between short-term credit constraints and labor supply is scarce. To identify the causal impact of short-term constraints on agricultural productivity through farms’ labor supply, we propose to conduct a cluster randomized controlled trial, which will provide selected households with access to maize loans during the farming season. In the first year of the study, loan programs will be announced after cropping decisions are made. This will allow us to isolate short-run adjustment on the labor supply margin, and any resulting impact on agricultural productivity. During the second year of the study, the loans will be announced to a subset of farmers before cropping decisions are made. This will allow us to measure the combined effect of adjustments in the overall production plans as well as in the short-term labor allocation. In order to distinguish credit supply from basic income effects, income transfers corresponding to the net value of the credits will be made to a subgroup of farmers. We will also provide cash loans to a selected group of farmers to measure the impact of the in-kind nature of the loan programs on uptake, repayment, resource allocation, productivity and harvest outcomes. The tested interventions are easily scalable, and, if successful likely to be implemented both by government and non-government agencies.
External Link(s)

Registration Citation

Fink, Günther, Kelsey Jack and Felix Masiye. 2018. "Food Constraints, Yield Uncertainty and “Ganyu” Labour." AEA RCT Registry. February 12.
Former Citation
Fink, Günther, Kelsey Jack and Felix Masiye. 2018. "Food Constraints, Yield Uncertainty and “Ganyu” Labour." AEA RCT Registry. February 12.
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Experimental Details


Selected farmers will be provided with access to short-term cash or maize loans.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
The primary endpoint is total value of harvest produced by farms. Secondary outcomes are on-farm labor supply and nutrition.
Primary Outcomes (explanation)
The primary question is whether access to loans can improve farm productivity, which we will measure as the total production value generated by each farm.

The main mechanisms through which we expect credit constraints to affect productivity is on-farm labor supply - which is therefore our secondary outcome.

Since short-term resources may also affect consumption and nutrition, we will analyze child nutrition as third outcome.

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Clusters will be randomly assigned to cash loans, maize loans or control group.
Experimental Design Details
In order to assess the effect of short-term credit constraints on labour allocation decisions, we propose to conduct a cluster-randomized trial. As part of the study, farmers will be allocated to 3 groups: a control group, a maize loan group, and a cash credit group. In the first year of the trial, credit interventions will not be announced until January, which is the beginning of the “hungry season” and, with the final harvest only 3 months away, the beginning of the most labour-intensive part of the farming season. At this point in the season, farmers have made their cropping decisions. The main objective of this first phase of the project is to assess the labour supply impact of short-term credit constraints, i.e. to assess the degree to which additional resources affect household labour allocation. The primary goal is to 1) measure the degree to which the elimination of credit constraints lowers the provision of off-farm labour, 2) increases the hiring of outside labour in the short-run, and 3) affects final harvest outcomes.

Maize loans will be offered in early January, and will give farmers the option to obtain one 50kg bag of maize per month from January to March. Since zero-interest loans constitute a net transfer to farms, we will provide direct income transfers to a subset of farmers. The comparison of farmers in main treatment groups with the subsample of farmers in the control group receiving direct income transfers will allow us to separate the credit access mechanisms from the direct income effect of the maize program.

While one of the innovation of the proposed study lies in the provision of food loans, the fundamental mechanism addressed in this proposal is the impact of short-term credit constraints on agricultural labor supply. The comparison between the control and the cash credit arm will allow us to directly assess the degree to which farming outcomes are affected by credit constraints. While we conjecture that maize loans will have a larger impact on farm productivity than cash loans, the relative difficulty of enforcing cash repayment is likely to affect both uptake and repayment rates, and thus also the relative feasibility of both programs. The parallel introduction of cash credits will allow us to directly assess these claims empirically, i.e. to assess whether maize is used differently from cash credit and if yes, which loan program compares more favorably with respect to final agricultural production.
While short-term increases in production are of interest, the most important question addressed in the proposed study is whether short-term improvements in yields can have persistent positive effects on agricultural productivity. Higher yields resulting from the intervention in Year I should lower the likelihood of households facing food shortages in the subsequent year. A very successful short-term intervention therefore has the potential to permanently alter household productivity. These effects may be even larger if farmers are aware of future credit options at the beginning of the farming season. The availability of credit during the farming season should, as outlined in the theoretical model above, alter farmer’s plot size and crop choices at the beginning of the season, and lead to larger overall adjustments. To distinguish wealth from anticipated credit access mechanisms, 50% of treated farmers will be offered a continuation of the loan programs in Phase II of the program, while 50% of farmers will not be offered any further loan options. We expect farmers who received a loan in Year I to be on average wealthier at the beginning of the second season. By comparing farmers with continued programs to farmers who no longer get the programs we will be able to identify the additional effects (and extensive margin adjustments) achieved by allowing farmers to adjust their production plan to newly available credit options before starting field operations. We will measure wages within the study villages and on nearby large farms to help identify more general labor market impacts.
Randomization Method
Randomization will be done in office by a computer.
Randomization Unit
Cluster/ villages of farmers
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
180 farms
Sample size: planned number of observations
3600 farmers
Sample size (or number of clusters) by treatment arms
60 control, 60 cash loan, 60 maize loan
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
The study is powered to detect an increase in farm production value of 10% (ITT).

Institutional Review Boards (IRBs)

IRB Name
Harvard Human Research Protection Program
IRB Approval Date
IRB Approval Number
Analysis Plan

Analysis Plan Documents


MD5: 963fa09ae04500633968032ab2a41c80

SHA1: add982878685954d62029bb747e009026d333442

Uploaded At: March 10, 2014


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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials