"Using a multi-method approach, we identified specific areas with limited availability of OSAT [Outpatient Substance Abuse Treatment] services in Spanish in the county with the largest population of Spanish-speaking Latinos in the United States. While most communities have access to services in Spanish, the northeast area of the county – representing SPA 3 with cities such as Rowland-Hacienda Heights, West Covina, La Puente, Alhambra, El Monte, and Rosemead – reported the greatest linear distance to treatment facilities offering services in Spanish. Maps of these Latino communities, which surround cold spots E and G, show the significant scarcity of general and Spanish-speaking providers. This is a geographic region that is home to almost one fifth (18%) of the county’s Latino residents, and where 70% of Latino residents report speaking primarily Spanish in the home [39].
"It is highly likely that the disparity between the need for Spanish-language substance abuse treatment and
geographical accessibility to Spanish OSAT services in certain regions of the County (e.g., SPA 3) is greater than what is presented in this study. U.S. Census data from 2000 yield conservative Latino population estimates in L.A. County, and although final 2010 Census estimates are not yet fully available, it is evident that the Latino population has grown rapidly in the last decade. Possibly the most interesting finding extracted from these maps is that the areas traditionally known to have high Latino populations (the three highlighted SPAs–4, 6, and 7–in Figure 1) may be relatively well served. It is the more fragmented, but expanding, communities that may not be accurately depicted in data from 2000 (i.e., SPA 3) wherein the greatest need for language capacity building exists. Considering that Latinos are the fastest-growing ethnic minority group [6], the unmet service need found in this study is likely to be more pronounced in population data from 2010, as preliminary information indicates significant growth in SPA 3.
When combined with the oversimplification of linear distance and considering that the most recent data are
the facility locations, our findings suggest that an inaccessibility problem exists for neighborhoods in these areas. It is expected that there will always be neighborhoods that are poorly served due to isolation. However, these results, especially if overlaid with other socioeconomic measures, will make for an interesting comparison between 2000 and 2010 census population distributions in future studies."

Source

Guerrero, Erick G., et al., "Availability of Substance Abuse Treatment Services in Spanish: A GIS Analysis of Latino Communities in Los Angeles County, California," Substance Abuse Treatment, Prevention, and Policy (2011), 6:21.
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