Beyond the “inverse relationship”: Area mismeasurement may affect actual productivity, not just how we understand it
利用赞比亚小农户玉米地块的全国代表性数据，比较自报面积与GPS测量值，发现面积测量误差导致小地块面积被高估、大地块被低估，且农民依据错误面积调整投入，进而影响实际生产率。
Abstract Measurement error in agricultural field area and productivity data for developing countries is widely acknowledged, but there is a shortage of evidence on what this implies, especially for farmers. By comparing self‐reported to global positioning system measurements, we investigate area measurement errors using a nationally representative dataset of Zambian smallholder maize plots. We examine the implications for researchers’ understanding of productivity, but also how actual productivity may be affected. We find land area tends to be overstated on smaller fields and understated on larger fields. Correcting measurement error strengthens evidence of an inverse relationship between field size and productivity. Input use patterns indicate farmers believe the inaccurately reported area figures, suggesting measurement errors affect input choices and thus actual productivity. Improving farmer understanding of area measurements could improve productivity. Improving the accuracy of area data will improve researchers’ understanding of productivity.