Which metric indicates a tax's ability to provide stable revenue during economic fluctuations?

The metric that indicates a tax's ability to provide stable revenue during economic fluctuations is the Revenue Stability Index. This index specifically measures how resilient tax revenue is to changes in the economy, such as recessions or booms. A tax system that has a high Revenue Stability Index typically means that it can maintain consistent revenue levels despite varying economic conditions, which is crucial for government budgeting and financial planning.

The Tax Burden Ratio reflects the proportion of income that taxpayers pay in taxes but does not directly measure revenue stability. The Elasticity Ratio pertains to the responsiveness of tax revenue to changes in the tax base and is not a direct measure of revenue stability. The Assessment Ratio relates to property assessments rather than the stability of overall tax revenue, making it not suitable for this specific inquiry about economic fluctuations. Thus, the Revenue Stability Index is the most appropriate choice for indicating how well a tax can weather economic volatility.