El experimento natural como un nuevo diseño cuasi-experimental en investigación social y de salud / Natural experiment as a new quasi-xperimental design in social and health-related sciences

En las ciencias sociales y de la salud actualmente comienza a ser conocido un diseño denominado como "experimento natural", que se caracteriza por ser un tipo de cuasi-experimento en que la asignación de tratamiento no es hecha por el investigador sino por un agente exógeno tal como una ley, una política sectorial o un fenómeno natural. Esa intervención exógena implícita permite que se formen grupos con bajos niveles de sesgos de selección inicial, por lo que la comparación de resultados encontrados en esos grupos (grupos afectados por la ley, la política o fenómeno natural respecto del grupo contrafáctico que no es afectado) permite predecir los efectos de la ley, política sectorial o fenómeno natural casi tan eficientemente como en la creación de grupos aleatorios de tratamiento y control.

Currently in social science research it is used a new research design defined as a "natural experiment", where the researcher has none participation in the treatment assignment because it has been directly done for an exogenous agent such as a law, a social policy or a natural event. This implicit exogenous intervention allows that low-level pre-determined selection bias groups be formed. Therefore, the comparison on results being found between these groups (law-affected group, social policy-affected group, or natural event-affected group versus contrafactic groups not being affected) allow to predict the effect of this law, social policy, or natural event almost so efficiently like happen in randomly created treatment-and-control groups.

Factores biológicos y psicosociales predictores del estilo de vida promotor de salud / Biological and psychosocial factors that predict health promoting lifestyles

Background: One of the goals of the national health reform is to promote a healthy lifestyle in all the population. The determinants of healthy lifestyles need to be identified to guide people towards this purpose. Aim: To analyze the health promoting lifestyle (HLP) in a community of Concepción and to identify the personal factors that might be predictors of such lifestyle. Material and methods: Pender's health promotion model was used as the conceptual framework for exploring the HLP among 360 persons aged from 15 to 64 years, free from chronic diseases. Data were obtained by a semi structured questionnaire and the following scales were used to measure HLP: perceived health status, perceived self esteem, and perceived self efficacy. Relationships between personal factors and HLP were studied. Data were processed with SAS software and analyzed with descriptive and inferential statistics. Results: Only 52.2 percent of the sample had a healthy lifestyle. The variables sex, age, occupation, access to health care, self esteem, perceived health status and perceived self efficacy had a significant effect on HLP. A regression model showed that self esteem, self efficacy, sex, age, occupation and access to health care explained 30 percent of the variation in health lifestyle. Conclusions: Only half of the studied sample had a healthy lifestyle. The variables obtained with the regression model, should be considered to create effective interventions encouraging persons to integrate healthy behaviors to their life.