Time-lapse maps for planning and policy

Background. Tabular data can convey information concisely. However, readers often struggle to decipher and correctly interpret such tables, particularly if location or time is important.

Objective. Determine if time-lapse maps can efficiently communicate data in multiple dimensions – space, time, different racial/ethnic groups and for program evaluation.

Methods. State grants for teen pregnancy prevention programs included a criterion of serving teen birth rate “hot spots” mapped for 2000-2001 births. Four years later, the state mapped areas by teen birth rates for 2004-2005. Maps were created using identical ranges of teen birth rates for the two time periods and for four racial/ethnic groups.

Results. Time-lapse maps immediately showed that state teen birth rates had declined markedly but varied by geographic area and racial/ethnic group. Analyses will be presented to evaluate whether state-funded teen pregnancy prevention programs had greater impacts on teen births than non-funded areas.

Conclusion. Time-lapse maps can rapidly convey information, some of which is correct, some of which can be misleading. Strengths and weaknesses of this mapping approach will be discussed.

Public Health Implications. Coupling maps with counts, confidence intervals and other quantitative data may allow multi-directional evaluation of the impact of local public health programs that can be readily understood by most readers.