Modifiable areal unit problem

The issue was first recognized by Gehlke and Biehl in 1934[5] and later described in detail in an entry in the Concepts and Techniques in Modern Geography (CATMOG) series by Stan Openshaw (1984) and in the book by Giuseppe Arbia (1988).

In particular, Openshaw (1984) observed that "the areal units (zonal objects) used in many geographical studies are arbitrary, modifiable, and subject to the whims and fancies of whoever is doing, or did, the aggregating".

Further, robustness checks of unit sensitivity to alternative spatial aggregation should be routinely performed to mitigate associated biases on resulting statistical estimates.

[6] Others have argued that it may be difficult to construct a single set of optimal aggregation units for multiple variables, each of which may exhibit non-stationarity and spatial autocorrelation across space in different ways.

Studies of the MAUP based on empirical data can only provide limited insight due to an inability to control relationships between multiple spatial variables.

Until a more analytical solution to MAUP is discovered, spatial sensitivity analysis using a variety of areal units is recommended as a methodology to estimate the uncertainty of correlation and regression coefficients due to ecological bias.

The delineation of zonal boundaries of TAZs has a direct impact on the reality and accuracy of the results obtained from transportation forecasting models.

In this paper the MAUP effects on the TAZ definition and the transportation demand models are measured and analyzed using different grids (in size and in origin location).

This analysis was developed by building an application integrated in commercial GIS software and by using a case study (Lisbon Metropolitan Area) to test its implementabiity and performance.

The results reveal the conflict between statistical and geographic precision, and their relationship with the loss of information in the traffic assignment step of the transportation planning models.

[14] Research has also identified the modifiable areal unit problem (MAUP) to be a factor in climate action and governance by affecting coordination between national and local actors.

MAUP distortion example
An example of the modifiable areal unit problem and the distortion of rate calculations
A hand map with different spatial patterns. Note: p is the probability of q -statistic; * denotes statistical significant at level 0.05, ** for 0.001, *** for smaller than 10 −3 ;(D) subscripts 1, 2, 3 of q and p denotes the strata Z1+Z2 with Z3, Z1 with Z2+Z3, and Z1 and Z2 and Z3 individually, respectively; (E) subscripts 1 and 2 of q and p denotes the strata Z1+Z2 with Z3+Z4, and Z1+Z3 with Z2+Z4, respectively.