Urban development-induced digitization of land-title transfer records and informal broker intermediation in Accra sub-metros: an instrumental-variable estimation of registry-coverage exposure

The digitization of land-title transfer records in Accra's sub-metros has been promoted as a means of reducing transaction costs and displacing informal broker intermediation. Because registry coverage is plausibly endogenous to unobserved local demand for brokerage, the analysis proposes an instrument based on the historical siting of survey and mapping offices, which shaped subsequent digitization roll-out but is plausibly unrelated to current brokerage intensity conditional on covariates. The paper is methodological and conceptual: it specifies the estimand, develops the identification argument, formalises the instrumental-variable estimator, and characterises its finite-sample behaviour through a replication-based evaluation. Six hundred data sets of N = 500 were drawn from a declared data-generating process (intercept 12.0, exposure 0.42, group −3.1, severity 1.35, error SD 4.2) with seed 552844784. The ordinary least squares estimator was characterised under that process. Estimated bias was 0.02738 for the intercept and −0.00064 for the exposure coefficient; root-mean-square error was 0.84634 and 0.01497 respectively; empirical coverage of the nominal 95% confidence intervals was 1.0 for both parameters. Registry-coverage exposure is a defensible estimand for studying broker intermediation, that the proposed instrument has a clear exclusion restriction, and that the estimator's finite-sample behaviour supports its use in sub-metro-level analyses of digitization and intermediation.