Synthetic social data: trials and tribulations

Large Language Models are being used in conversational agents that simulate human conversations and generate social studies data. While concerns about the models' biases have been raised and discussed in the literature, much about the data generated is still unknown. In this study we explore the statistical representation of social values across four countries (UK, Argentina, USA and China) for six LLMs, with equal representation for open and closed weights. By comparing machine-generated outputs with actual human survey data, we assess whether algorithmic biases in LLMs outweigh the biases inherent in real- world sampling, including demographic and response biases. Our findings suggest that, despite the logistical and financial constraints of human surveys, even a small, skewed sample of real respondents may provide more reliable insights than synthetic data produced by LLMs. These results highlight the limitations of using AI-generated text for social research and emphasize the continued importance of empirical human data collection.