Done well, citizen science projects can gather datasets of a size and scope far larger than would be possible using professional researchers. This study uses data gathered in Britain by the Garden Moth Scheme (GMS). Participants run garden light traps for at least 26 weeks a year and complete garden questionnaires detailing garden habitat and nearby landscape features. We used data exploration and generalised linear modelling (GLM) to investigate whether the data can be used to generate reliable research findings, testing the effect of moth light trap type on moth catch. Robinson traps, then Skinner traps, then Heath traps were found to catch the highest abundance and diversity of moths. Mercury vapour bulbs, then blended light bulbs, then actinic bulbs collected the highest abundance and diversity of moths. The GMS dataset can be used to generate useful and reliable research findings, and can be used in the future to investigate temporal and spatial trends in moth assemblage. Under international law, the use of mercury vapour bulbs will be phased out in coming years, leading to changes in the way moth assemblages are sampled. Information on the relative efficacy of different bulb types will aid the analysis of long-term moth datasets after these changes.