Unmasking Hiring Bias: Platform Data Analysis and Controlled Experiments on Bias in Online Freelance Marketplaces via RAG-LLM Generated Contents

Online freelance marketplaces, a rapidly growing part of the global labor market, are creating a fair environment where professional skills are the main factor for hiring. While these platforms can reduce bias from traditional hiring, the personal information in user profiles raises concerns about ongoing discrimination. Past studies on this topic have mostly used existing data, which makes it hard to control for other factors and clearly see the effect of things like gender or race. To solve these problems, this paper presents a new method that uses Retrieval-Augmented Generation (RAG) with a Large Language Model (LLM) to create realistic, artificial freelancer profiles for controlled experiments. This approach effectively separates individual factors, enabling a clearer statistical analysis of how different variables influence the freelancer project process. In addition to analyzing extracted data with traditional statistical methods for post-project stage analysis, our research utilizes a dataset with highly controlled variables, generated by an RAG-LLM, to conduct a simulated hiring experiment for pre-project stage analysis. The results of our experiments show that, regarding gender, while no significant preference emerged in initial hiring decisions, female freelancers are substantially more likely to receive imperfect ratings post-project stage. Regarding regional bias, a strong and consistent preference favoring US-based freelancers shows that people are more likely to be selected in the simulated experiments, perceived as more leader-like, and receive higher ratings on the live platform.