Comparison 1. Tympanometry improvement.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Tympanogram improvement: 1 month or less	5		Relative risk (Random, 95% CI)	Subtotals only
1.1 B or C2 to C1 or A	5		Relative risk (Random, 95% CI)	1.47 [0.69, 3.13]
1.2 B to C1 or A	3		Relative risk (Random, 95% CI)	2.15 [1.41, 3.28]
1.3 C2 to C1 or A	2		Relative risk (Random, 95% CI)	3.84 [1.94, 7.59]
2 Tympanogram improvement: > 1 month	4		Relative Risk (Random, 95% CI)	Subtotals only
2.1 B or C2 to C1 or A	4		Relative Risk (Random, 95% CI)	1.22 [1.00, 1.49]