A Practical Guide and Case Study on How to Instruct LLMs for Automated Coding During Content Analysis

This paper provides a practical example and guide on how to augment or replace human coders with Large Language Models (LLMs) during content analysis. We demonstrate this by replicating and extending an influential study on environmental communication. Our setup, running locally on consumer-grade hardware, makes it feasible for university researchers operating within typical computational and legal constraints. We validate the LLM’s performance by replicating the original study’s codings, scaling the analysis to cover a tenfold increase in articles, and extending the LLM’s application to a comparable German-language corpus, comparing these results to human expert coders. We offer guidelines for instructing LLMs, validating output, and handling multilingual coding, presenting a replicable framework for future research. This paper is intended to systematically guide other researchers when integrating LLMs into their workflows, ensuring reliable and scalable coding practices. We demonstrate several advantages of LLMs as coders, including cost-effective multilingual coding, overcoming the limitations of small-sample content analysis, and improving both the replicability and transparency of the coding process.