Table 5

Quality of studies among those that reported a negative impact

	Yes	No	χ²	p Value
Meeting all four Siegel criteria	0% (0/35)	100% (35/35)^18,^23,^27,^31,^57–^61,^80–^97,^99,^103–^108,¹¹⁴	15.13	0.000
Including an objective measure	20% (7/35)^18,^27,^57–⁶¹	80% (28/35)^23,^31,^80–^97,^99,^103–^108,¹¹⁴	7.64	0.006
Funded by source clearly independent of tobacco industry	0% (0/35)	100% (35/35)^18,^23,^27,^31,^57–^61,^80–^97,^99,^103–^108,¹¹⁴	88.80	0.000
Peer reviewed	3% (1/35) ⁸⁴	97% (34/35)^18,^23,^31,^57–^61,^80–^97,^99,^103–^108,¹¹⁴	14.09	0.000