Over a 12-month period 501 children (age range 11 months to 15 years) underwent surgery for a possible middle ear effusion. All had tympanometry performed within 2 h of surgery. The results of tympanometry were correlated with the surgical findings in 955 ears. A type-B tympanogram has a high sensitivity (0.91) in predicting middle ear effusion with good specificity (0.79). A type-A tympanogram has a very high specificity (0.99) in predicting a dry middle ear but low sensitivity (0.34). Both the positive (0.91) and negative (0.84) predictive values of a type-A tympanogram are high. The addition of a type-C tympanogram increases the sensitivity of predicting a dry middle ear to 0.79. The positive predictive value of a peaked (type-A or -C) tympanogram is 0.71 and should be considered strong evidence that the middle ear is dry. Tympanometry is the best clinical test for the presence or absence of a middle ear effusion, and on the basis of preoperative tympanometry alone the need for surgery should be carefully reassessed.

My four major issues mainly testify to the incomparable scholarship of this pioneer of the current healthy state of evangelical historiography. The collection ends with a delight. A survey of changing patterns of worship since 1965 is based, not on the vast library of primary and secondary sources found in the typical Bebbington address or article, but on his own notebooks, recording his impressions of hundreds of church services he has attended personally. This chapter is a cogent demonstration of the much-debated proposition that religious history is better understood by those who practise and believe it than by those who, in the interests of objectivity, keep their distance.