Using Google Search Query Surveillance to Monitor Smokers' Real-Time Responses to Cigarette Tax Increases

Raising cigarette taxes is an evidence-based approach to decreasing tobacco use. Smokers can respond by using the web to seek out cessation assistance or avoid taxes by purchasing cheap cigarettes online. We examined how smokers' smoking cessation and tax avoidance Internet search queries were motivated by the United States' (US) 2009 State Children's Health Insurance Program (SCHIP) federal cigarette excise tax increase and several other state specific tax increases. Google keyword searches among residents in a taxed geography in the US were compared to an untaxed geography (Canada) for two years around each tax increase. Search data were normalized to a relative search volume (RSV) scale, where the highest search proportion was labeled 100 with lesser proportions scaled by how they relatively compared to the highest proportion. Changes in RSV were estimated by comparing means during and after the tax increase to means before the tax increase, across taxed and untaxed geographies. The SCHIP tax was associated with an 11.8% (95% CI, 5.7 to 17.9; p<.001) immediate increase in cessation searches; however, searches quickly abated in subsequent months, approximating differences from pre-tax levels in Canada. Tax avoidance searches spiked 27.9% (95%CI, 15.9 to 39.9; p<.001) and 5.3% (95%CI, 3.6 to 7.1; p<.001) during and in the months after the tax compared to Canada, respectively, suggesting avoidance was the stronger and more durable response. Trends were similar for Florida and New York. Search query surveillance is a valuable real-time, free and public method that states should adopt for tobacco control surveillance.