Reviewer's report 
 Strong decline in female sterilization rates in Norway after the introduction of a new copayment Title: 
system: a registry based study 
 1  8 May 2007 Version: Date: 
 Elina Hemminki Reviewer: 
Reviewer's report: 
General 
This paper reports sterilizations rates among women in Norway before and after the increase of the patient share in costs. The topic is interesting, analysis straight forward but some crucial data are lacking. 
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Major Compulsory Revisions (that the author must respond to before a decision on publication can be reached) 
1. The authors do not tell why the co-payment was raised: was it just for hospitals to earn more money or 
was it part of a conscious effort to decrease the number of sterilizations? If the latter, maybe the noted 
decrease is not due to co-payment, but a reflection of other efforts (and the conclusion is not valid). 
2. The data come from hospital register (patient register), which does not cover private clinics. Is it possible 
that the women started to go to private clinics (the price now being competitive and possible more 
convenient)? The authors tell that an alternative data source is Statistics Norway, which even though not 
complete, also covers private care. They should show the data from Statistics Norway to exclude the possibility of shift in the place of care. Especially because the authors say that the patient register cannot 
be used for men, because of the private sector. Now some data are given in Discussion but not for the 
years under study. 3. The text in Results says that the decrease in the incidence rates was strongest in the oldest age group. That conclusion, however, is difficult to see from the data given in the tables. It would be good to use some 
indicator showing that. 
4. The comparison of own results to that of the other countries is hazy: the reader cannot easily see how the 
Norwegian trend relates to that of other countries: is it so that the abrupt drop is unique or are there other 
experiences like that? 
5. The discussion does not deal with the main question: is the drop real, could it be explained by other 
factors or is the increased co-payment the only and certain cause. 
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Minor Essential Revisions (such as missing labels on figures, or the wrong use of a term, which the author 
can be trusted to correct) 
6. The term “interval sterilization is not clear: it is used in abstract, but explained only later. Either use a 
self-evident term in Abstract or explain it. 
7. p.4, various codes are given; add which classification they refer to. 8. p 4, incidence is said to be calculated as the population at risk; however, alter it is said that women with sterilization are included. Thus change to “per same aged women”. 
9. The discussion is loose, and could be more focused and shorter. 
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Discretionary Revisions (which the author can choose to ignore) 
 Unable to decide on acceptance or rejection until the authors have responded to the major What next?: 
compulsory revisions 
 An article of importance in its field Level of interest: 
 Acceptable Quality of written English: 
 No, the manuscript does not need to be seen by a statistician. Statistical review: 
Declaration of competing interests: 
'I declare that I have no competing interests'