Building parable economies embedding econometricians, we view alternative estimators (Instrumental variables, fuzzy regression discontinuity, natural experiments, OLS, event studies) from the perspective of privately informed decision-makers, e.g., CFOs. Instrumental variable estimates can be misleading since randomization through observable instruments eliminates signal content arising from discretion. If the goal is informing discretionary decisions, rather than predicting outcomes after forced/mistaken actions, instrumentation is problematic, whereas OLS or event studies can be sufficient. The analysis shows that the utility of alternative estimators hinges upon often neglected assumptions about agent/econometrician information sets, as distinct from exclusion restrictions. We recommend parable economy estimation before real-world IV estimation.

We establish limitations to the usage of direct revelation mechanisms (DRMs) by corporations seeking decision-relevant information in economies with securities markets. In this environment, posting a DRM increases the informed agent’s outside option: if the agent rejects the DRM, he convinces the market he is uninformed, and he can aggressively trade with low price impact, thereby generating large (off-equilibrium) trading gains. This endogenous outside option may make using a DRM to screen uninformed agents impossible. When screening is possible, solely relying on the market for information is optimal if the increase in outside option is sufficiently large.