[A study on the reliability of data provided by patients' family surrogates]

In epidemiological investigations, the validity and reliability of data under different ways of collection might not be consistent. In order to evaluate the consistency of data collected from cases themselves or from their surrogates (for example, the spouse) through answering the same questionnaire, at personal interview, was carried out among 50 cases of lung cancer and their surrogates respectively. Other than the item starting age of smoking by a paired-t test, the results showed that between the two groups of quantitative data sources, the overall consistent rate was 84.1% and the differences were not significant (P < 0.05). When Kappa consistency test was used to the count variables, an average consistent rate of 87.8% was noticed, but P values were less than 0.001 for all items. Results from this study were quite similar to those with have been published abroad and suggested that it is credible to collect data from surrogates when dead cases were selected as research subjects.