Comparison of Trends in Self-reported Cigarette Consumption and Sales in England, 2011 to 2018.

Importance: Population cigarette consumption is declining in many countries. Accurate estimates of long- and short-term changes are vital for policy evaluation and planning. Survey data and sales data that are used to make these estimates each have important potential biases, so triangulation using different methods is required for robust estimation. Objectives: To compare monthly estimates of cigarette consumption in England from a nationally representative survey and recorded cigarette sales and to triangulate an accurate estimate of changes in cigarette consumption since 2011. Design, Setting, and Participants: This study used time series analyses based on survey data and recorded cigarette sales to estimate and compare trends in population cigarette consumption in England from 2011 to 2018. Survey participants were representative samples of 1700 people aged 16 years or older each month in England. Main Outcomes and Measures: Monthly cigarette retail sales data from August 2011 through February 2018 were obtained from a data agency. Monthly self-reports of cigarette consumption were collected over the same period using the Smoking Toolkit Study. Results: A total of 136 677 individuals (51.1% female; mean [SD] age, 46.7 [18.8] years) were surveyed. Over the study period, mean monthly cigarette consumption in England was 2.85 billion (95% CI, 2.78 billion to 2.93 billion) cigarettes based on survey data compared with 3.08 billion (95% CI, 3.03 billion to 3.13 billion) estimated from sales data. Over the whole period, cigarette consumption declined by 24.4% based on survey data and 24.1% based on sales data. This equated to 118.4 million and 117.4 million fewer cigarettes consumed per month (or approximately 1.4 billion per year) based on survey data and sales data, respectively. After adjusting for underlying trends, month-by-month changes in cigarette consumption were closely aligned: a 1% change in survey-estimated cigarette consumption was associated with a 0.98% (95% CI, 0.53%-1.44%) change in sales estimates. Conclusions and Relevance: Survey data and sales data were closely aligned in showing that overall cigarette sales in England have declined by almost a quarter since 2011, amounting to more than 1 billion fewer cigarettes smoked each year. The alignment between the 2 methods provides increased confidence in the accuracy of parameters provided by the Smoking Toolkit Study and sales data. It indicates that estimated changes in cigarette consumption are robust and provide a meaningful basis for policy evaluation and planning.