Background - Human resources for health (HRH) are a major component of health systems. Research has shown that insufficient nursing staffing levels negatively impact patients’ morbidity and mortality. The global shortage of nurses is also affecting Switzerland, and is bound to worsen due to increased services demand and falling numbers of (Swiss) nurses available and/or willing to work under the present conditions. Studies abroad indicate that increasing the duration of nurses’ employment is the most efficient single measure to reduce the nursing shortage. Although reasons to stay or quit the profession have been described, they are highly culturally-dependent. Intention to quit is the main outcome measure in the literature, but actual career paths have rarely been studied beyond a one-year follow-up and outside acute care hospitals. Data on the nursing sector are affected by various biases and classification problems internationally, and even a common definition of a ‘nurse’ is lacking. Data are especially scarce in Switzerland where there is no active registry of nurses. Objectives – The n@w project aims at informing policymakers, nursing managers and the scientific community, by quantitatively measuring the relative importance of the reasons for nurses to stay or quit (a) a given facility, (b) a particular sector of care, and (c) nursing altogether, over the last 30 years in Switzerland. Actual career paths and duration of employment will be analyzed, and respondents will be prompted for potentially efficient policies and retention measures. The relative impact of retention determinants will be assessed, such as external and internal factors in the work environment, as well as personal factors, attrition/return factors, and cohort effect. Design – An observational study using a mixed-method (QUANTITATIVE – qualitative) approach. The quantitative arm will be a retrospective cohort study representing the main part of the research; 30-50 qualitative semi-structured interviews will provide additional detailed information on specific career paths selected on the basis of pre-defined criteria. Population - All nurses in Switzerland will be invited to participate. However analytic focus will be on six cohorts of nursing graduates from Swiss nursing schools across the three linguistic regions from graduation years 1983, 1988, 1993, 1998, 2003 and 2008, whatever their current occupational status (employed in or outside nursing, or outside of the workforce). Methods - Nurses will be invited to participate by a media campaign explicitly mentioning that nurses outside nursing are also invited, through their employers, and by direct invitation sent by the Swiss Nursing Association, to its members (n=26'000). All nurses will be asked to provide contact addresses of their graduate mates so they may also be invited, thereby initiating a snowball recruitment process. A web-based questionnaire will be used to inquire about career paths, job satisfaction and reasons for changes. Cohort-specific participation rates will be computed using information from the Swiss Red Cross files of nursing graduates (full coverage) for denominators. Quantitative analyses will include Optimal Matching Analysis of trajectories and standard techniques for the analysis of cohort data and change. Qualitative interviews will be conducted by phone and analysis will be centered on understanding key career changes. Expected benefits - By the end of the 26-month study, field partners, nursing managers and policymakers will have a clearer view of priorities and possible evidence-based solutions to the retention aspects of the nursing shortage, with new data to feed forecasting models currently based on assumptions.