# Rebuttal of "On Nonparametric Identification of Treatment Effects in Duration Models"

## TL;DR

This paper refutes a previous critique of a key result in duration models, demonstrating that the critique's main error invalidates its conclusions and reaffirming the original findings.

## Contribution

The authors clarify and correct a fundamental mistake in a prior critique, reaffirming the validity of the original identification result in duration models.

## Key findings

- The critique's main error was a basic mistake in variable transformation.
- The original proposition remains valid after correction.
- The critique's conclusions are invalidated by the identified error.

## Abstract

In their IZA Discussion Paper 10247, Johansson and Lee claim that the main result (Proposition 3) in Abbring and Van den Berg (2003b) does not hold. We show that their claim is incorrect. At a certain point within their line of reasoning, they make a rather basic error while transforming one random variable into another random variable, and this leads them to draw incorrect conclusions. As a result, their paper can be discarded.