surveillance district/county using the method of probability proportional to size. Three villages or residential areas were then sampled from each chosen township using the same method as in the previous stage. Subsequently, a residential group (at least 50 families) was sampled from each chosen village or residential area by simple random sampling. Finally, an individual of at least 18 years old was sampled in each family by means of a Kish grid. About 9.4% of the sampled families could not be located after three attempts and these households were replaced by others with similar family structures. A total of 98658 interviews were included in the final analyses \[[@CR18]\].

Measures {#Sec4}
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SRH and HRQOL were assessed based on the participants' answers for the following four questions:Would you say that, in general, yourEvaluating Communication Skills.
This study investigates the construct validity of an instrument to measure the quality of communication skills, during one curriculum year of a four year longitudinal communication skills training programme. 42 Representative videotapes of students' simulated patient encounters at the beginning of the third year and 35 of the end of the year were assessed by nineteen trained observers, using the MAAS-Global criteria list. A difference in communication skill competence was found between the performance at the beginning and at the end of the third year. The specific aspects in which the students improved revealed a greater routine in conducting a doctor-patient encounter and a greater structuring capability: those communication skills that have been trained in the years before the study period, thus supporting the validity of