Table 4.

Classroom engagement is better after lessons in nature than lessons in the classroom by most measures: Findings for each measure of classroom engagement.

	Means		Paired differences
	Nature	Classroom	Mean	Std. dev.	t-value	df	Effect sizea
Teacher ratings	1.20	0.05	1.15	1.79	2.88**	19	0.74
Student ratings	81.01	79.27	1.74	6.56	1.18	19	0.60
Redirects	3.10	5.70	−2.60	2.62	4.43***	19	0.84b
Independent photo ratings	1.10	−0.10	1.20	1.64	3.27**	19	0.77
Composite index	0.40	−0.40	0.80	0.93	3.83**	19	0.81

^aCommon language effect size (McGraw and Wong, 1992) also known as the probability of superiority (Grissom and Kim, 2005) expresses the effect size in percentages. In this table, it reflects the probability that the score for a given classroom engagement measure will be better after a lesson in nature than after a lesson in a classroom. Controlling for differences between classrooms in classroom engagement, the likelihood that a class will score higher on teacher ratings of classroom engagement after a lesson in nature than after a lesson in a classroom is 74%.

^bFor ease of interpretation, all effect sizes reflect the likelihood of better class engagement after a lesson in nature than a matched classroom lesson; because class engagement is better when redirects are fewer, the effect size reported here reflects the likelihood that redirects are fewer after a lesson in nature.

^**p < 0.01,

^***p < 0.001.