# Manipulating the Difficulty of C-Tests

## TL;DR

This paper introduces two automatic strategies to adjust the difficulty of C-tests by manipulating gap size and distribution, aiding personalized language learning and assessment.

## Contribution

It presents novel methods for automatically controlling C-test difficulty through gap manipulation based on difficulty predictions.

## Key findings

- Both strategies effectively achieve target difficulty levels.
- The approaches are validated through corpus experiments and user study.
- Strategies adapt well to different learner needs.

## Abstract

We propose two novel manipulation strategies for increasing and decreasing the difficulty of C-tests automatically. This is a crucial step towards generating learner-adaptive exercises for self-directed language learning and preparing language assessment tests. To reach the desired difficulty level, we manipulate the size and the distribution of gaps based on absolute and relative gap difficulty predictions. We evaluate our approach in corpus-based experiments and in a user study with 60 participants. We find that both strategies are able to generate C-tests with the desired difficulty level.