Effect size

Data used to calculate effect size (Glass's Δ) of five studies on the impact of artificial light at night (ALAN) on firefly occurrence and/or courtship. Values were obtained published figures by means of WebPlotDigitizer (https://apps.automeris.io/wpd/). Because all studies involve comparison of groups of the same size (e.g. firefly populations before and after ALAN exposure), Glass’s Δ is an appropriate estimate of effect size, as it uses only the standard deviation of the control group (Kline 2013).