Comparing household incomes across nations requires precise measurement. This article highlights hidden flaws in the standard ten-category income question used by the World Values Survey (WVS), questioning its ability to accurately capture or cause cross-national comparisons.

The WVS's common approach often obscures true differences and relationships because:

* Income categories can be inconsistent across countries, leading to misinterpretation of responses.

* Responses might represent household income but not individual earnings, potentially skewing analyses about voting behavior or policy preferences.

* The ten-point scale may lump together meaningful variations in economic standing, hiding important distinctions.

The authors argue these problems affect both descriptive findings (about public opinion patterns) and causal inferences drawn from WVS data. They then introduce several practical corrections designed to address these issues directly.

Key Findings & Diagnostics:

* Using standard ten-category measures can lead to significant misinterpretation or bias.

* The proposed adjustments, implemented on WVS data, provide clearer and more accurate income indicators.

* Specific diagnostics confirm the need for such corrections by revealing measurement inconsistencies.

Broader Implications:

While focused on WVS data, similar comparability issues likely exist in other large cross-national survey datasets (like Eurobarometer or World Values Survey waves). These findings suggest that researchers relying on income measures from multiple surveys should carefully examine potential biases and consider applying harmonization techniques.

These corrections can be applied directly to existing WVS datasets.