Table 1.

E-cigarette regression coefficients, standard errors, t statistics, and p values 

	Coefficient	Standard error	t statistic	p value
Baseline
GBA
Level	4.140104	3.051848	1.36	0.177
Trend	− 1.373532	0.2321417	− 5.92	0.000*
USA
Level	95.65063	3.482517	27.47	0.000*
Trend	− 1.295596	0.3823137	− 3.39	0.001*
After EVALI
GBA
Level change	− 0.8664863	4.936645	− 0.18	0.861
Trend change	0.7472639	0.6716606	1.11	0.268
USA
Level change	3.427075	4.571001	0.75	0.455
Trend change	− 1.770607	0.9661419	− 1.83	0.069
After mass ban
GBA
Level change	− 14.18386	6.428874	− 2.21	0.029*
Trend change	− 1.189679	0.941033	− 1.26	0.208
USA
Level change	0.1329325	7.218978	0.02	0.985
Trend change	2.631157	1.278143	2.06	0.042*
After ban ended
GBA
Level change	− 0.0827453	4.759094	− 0.02	0.986
Trend change	2.808323	0.6655645	4.22	0.000*
USA
Level change	− 3.341619	2.741816	− 1.22	0.225
Trend change	0.0170775	1.126806	0.02	0.988
After COVID− 19
GBA
Level change	6.271158	4.28192	1.46	0.145
Trend change	− 0.7918229	0.7104741	− 1.11	0.267
USA
Level change	− 1.653717	3.959569	− 0.42	0.677
Trend change	− 0.3092617	0.8731348	− 0.35	0.724
After tax
GBA
Level change	0.5203217	3.957587	0.13	0.896
Trend change	0.9910441	0.7555539	1.31	0.192
USA
Level change	2.519472	3.075552	0.82	0.414
Trend change	− 1.39879	0.8390774	− 1.67	0.098

Regression coefficients for the level and trend changes in e-cigarette purchasing in the Greater Boston area and the USA at the baseline and after the four intervention points, along with the standard error, t statistics, and p values corresponding to each value. Asterisks (*) indicate significance at p < 0.05