Stability and change in public health studies in Colombia and Mexico: an exploratory approach based on co-word analysis

OBJECTIVE: To determine the level of stability or change in topic areas published by public health journals in Latin America and the Caribbean, using keywords and co-word analysis, in order to support evidence-based research planning. METHODS: Keywords were extracted from papers indexed in Scopus(®) that were published by the Revista de Salud Pública (RSP; Colombia), the Salud Pública de México (SPM; Mexico), and the Revista Peruana de Medicina Experimental y Salud Pública (RPMESP; Peru) for three periods: 2005 – 2007, 2008 – 2010, and 2011 – 2013. Co-word analysis was used to examine keywords extracted. Textual information was analyzed using centrality measures (inbetweenness and closeness). The hypothesis of stability/change of thematic coverage was tested using the Spearman's rho correlation coefficient. VOSviewer was used to visualize the co-word maps. RESULTS: A moderate level of change in thematic coverage was observed in 2005 – 2010, as evidenced by the correlation coefficients for two of the 3-year periods, 2005 – 2007 and 2008 – 2010: 0.545 for RSP and 0.593 for SPM. However, in 2008 – 2013, more keywords remained constant from one period to the next, given the size of the correlation coefficients for the last 3-year periods: 2008 – 2010 and 2011 – 2013: 0.727 for RSP and 0.605 for SPM. CONCLUSION: The research hypothesis was partially accepted given that just two consecutive 3-year periods showed a statistically-significant degree of stability in thematic coverage in public health studies. In that sense, this study provides compelling evidence of the effectiveness of using a combined approach for examining the dynamics of thematic coverage: centrality measures for identifying the main keywords and visual inspection for detecting the structure of textual information.