Over the last 30 years, meta-analyses and data pooling projects have emerged to be a prominent feature in the medical literature. Such approaches to data analysis are becoming increasingly useful to answer questions which were not previously possible due small sample sizes. However, the statistical power that we gain from big data pooling projects and meta-analyses may be offset by the inevitable pitfalls such as bias, poor data quality, spurious findings and lack of covariates. This presentation will describe the benefits and flaws of analysing 'big data' pooling projects and meta-analyses.