Estimate Demand Sensitivity From a Before-and-After Price Test

How to Use This Tool

Relate percentage quantity change to percentage price change while keeping the limitations visible. Estimate simple price elasticity from an old price, new price, old quantity and new quantity using editable observations.

The failure Price Elasticity is designed to catch

A two-point estimate mixes price response with seasonality, traffic and competitor changes unless the observations are otherwise comparable. The boundary is the job stated in Estimate Demand Sensitivity From a Before-and-After Price Test; Price Elasticity is not intended to score or transform a different workflow.

The Price Elasticity input contract

The fields used for this specific operation are Old price, New price, Old quantity sold, New quantity sold. Keep the source values beside the Price Elasticity result, because replacing the original would remove the evidence needed to reproduce or reverse the operation.

• For Price Elasticity, Old price starts at 10 in the worked case; replace that example with the matching source value.
• For Price Elasticity, New price starts at 12 in the worked case; replace that example with the matching source value.
• For Price Elasticity, Old quantity sold starts at 1000 in the worked case; replace that example with the matching source value.
• For Price Elasticity, New quantity sold starts at 850 in the worked case; replace that example with the matching source value.

Worked result for Price Elasticity

The executable case called Default decision scenario expects out: -0.7. Verify that observation before entering real material, and then change one Price Elasticity field at a time so an unexpected direction or formatting change can be traced to a specific input.

Reading the Price Elasticity output

It combines old price, new price, old quantity sold and new quantity sold into one decision result using the formula explained on the page. Apply that answer only when Old price, New price, Old quantity sold, New quantity sold describe the same scope and format as the worked operation. If the source uses different units, quoting, nesting, timing or account rules, a plausible-looking Price Elasticity output is not sufficient validation.

Assumptions attached to Price Elasticity

• Price Elasticity assumes that all inputs describe the same unit or reporting period unless the field explicitly says otherwise.
• Price Elasticity assumes that the model includes only the four visible inputs and does not infer hidden platform charges.

If one of these Price Elasticity assumptions is false, keep the result as a diagnostic rather than production or decision data, and choose an implementation that explicitly supports the missing rule.

Evidence maintained for Price Elasticity

The recorded reference is US SBA — marketing and sales. Reopen that source when the definition, format, fee or policy behind Price Elasticity changes; private configuration and downstream acceptance still have to be checked in the user's own system.

Where Price Elasticity runs

The named operation executes in browser JavaScript without an ecech calculation API. For Price Elasticity, local execution reduces transmission but does not control browser extensions, device security or the destination where the result is pasted, so sensitive inputs still require the user's normal handling rules.