Nurse prescribing in New Zealand-the difference in levels of prescribing explained.

This article discusses the three types of nurse prescriber currently registered in New Zealand (nurse practitioners, registered nurse prescribers (RNP) in primary health and specialty teams and registered nurse prescribers (RNPCH) in community health). It also provides an overview of the evolution of each group, as well as a summary of the current legislation, prescribing restrictions and models of supervision required for each type of prescriber.

Methodological issues in analyzing time trends in biologic fertility: protection bias.

One method of assessing biologic fertility is to measure time to pregnancy (TTP). Accidental pregnancies do not generate a valid TTP value and lead to nonrandom missing data if couples experiencing accidental pregnancies are more fertile than the general population. If factors affecting the rate of accidental pregnancies, such as availability of effective contraception and induced abortion, vary over time, then the result may be protection bias in the estimates of fertility time trends.

Meta-analysis of studies of alcohol and breast cancer with consideration of the methodological issues.

Objective: To give an up-to-date assessment of the association of alcohol with female breast cancer, addressing methodological issues and shortfalls in previous overviews.

Methods: Meta-analysis of studies (any language) providing original data on incidence of first primary breast cancer and alcohol. Two reviewers independently extracted data.

Studying time to pregnancy by use of a retrospective design.

Biologic fertility can be measured using time to pregnancy (TTP). Retrospective designs, although lacking detailed timed information about behavior and exposure, are useful since they have a well-defined target population, often have good response rates, and are simpler and less expensive to conduct than prospective studies. This paper reviews retrospective TTP studies from a methodological viewpoint and shows how methodological problems can be avoided or minimized by appropriate study design, conduct, and analysis.