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A lab-in-field experiment on land trade complexity and market centralization
Initial registration date
August 16, 2019
November 27, 2019 2:57 PM EST
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Institute for International Economic Studies
Other Primary Investigator(s)
London School of Economics
University of Melbourne
Maastricht University & UNU-MERIT
Additional Trial Information
We study the effects of complexity and market centralization in a land trading game. The game involves groups of 18 participants in villages in Masaka, Uganda. Participants are endowed with game currency and a set of artificial land plots on a "map", and trade plots among themselves to earn returns. They earn returns if they improve the efficiency of the land allocation in the game, which can be achieved by sorting higher "ability" players to better plots and/or by consolidating fragmented plots into contiguous blocks.
Our treatment variations are
1. Map complexity: some maps are "simple" because there are many possible payoff-equivalent first-best allocations of plots. Some maps are "complex" because there are only a few. Complexity is varied by minimally altering maps to add non-trading plots. These decrease the number of possible ways to arrange contiguous blocks of plots into the map.
2. Trade centralization: trade is either "decentralized," with participants trading free-form among themselves within the village, or "centralized," taking place with all participants present in the same location at the same time. We will study the effects of these treatments on trading efficiency, measured by the share of possible gains from trade achieved in the game, and the distribution of those gains, measured by the log-utility Atkinson index of final payoffs. Registration Citation
Intervention Start Date
Intervention End Date
Primary Outcomes (end points)
Overall trading efficiency. Trading efficiency broken down into a) Trading efficiency due to defragmentation, b) Trading efficiency due to sorting, c) Trading efficiency due to exposure losses
Distribution of final payoffs measured by the log-utility Atkinson index.
Primary Outcomes (explanation)
Overall trading efficiency (share of potential gains from trade realized)
Trading efficiency due to defragmentation (share of potential gains from defragmenting land)
Trading efficiency due to sorting (share of potential gains from sorting high types to high quality land)
Trading efficiency due to exposure losses (share of potential gains foregone due to some participants holding "too much" land)
Distribution of final payoffs measured by the log-utility Atkinson index (1 minus the ratio of the geometric and arithmetic means of final payoffs)
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
We play a series of land trading games, in villages, over the course of 2 weeks and three meetings. The games involve trading artificial land titles, which correspond to plots on a generated "map." Participants trade amongst themselves using game currency, and earn returns according to the gains from trade they achieve. Gains from trade can be achieved by sorting higher "ability" players onto better land, and consolidating fragmented plots into contiguous blocks. Trade is done in free-form bargaining between players. Maps can be either "simple" or "complex" and trade can be "decentralized" or "centralized."
Experimental Design Details
Randomization done in office by a computer
Village and week.
Each village will play either a simple map in week 1 and a complex map in week 2, or complex in week 1 and simple in week 2.
At the end of week 2 trade, all villages play a "trading day"
Was the treatment clustered?
Sample size: planned number of clusters
Each village plays a simple map followed by a complex map, or a complex map followed by a simple map. The second week's game is also followed by a trading day.
Sample size: planned number of observations
204 in total. 3 observations per village: a week 1 trading efficiency outcome, a week 2 pre-trading day efficiency outcome, and a week 2 post-trading day efficiency outcome.
Sample size (or number of clusters) by treatment arms
All villages play the simple treatment once and the complex treatment once, so 68 simple and 68 complex.
The trading day is played at the end of week 2, so we will have 34 observations for simple post-trading day and 34 for complex post-trading day.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
INSTITUTIONAL REVIEW BOARDS (IRBs)
Research Ethics Committee, London School of Economics
IRB Approval Date
IRB Approval Number
Mildmay Uganda Research Ethics Committee (MUREC)
IRB Approval Date
IRB Approval Number