Birth Characteristics and Fertility Trends

Region: This website provides natality statistics for Michigan counties and health districts; and for cities and townships with populations over 10,000. You may select any of these regions using the County, Local Health Department or City links above.

Geocoded Statistics: In the past, the mother's residence was sometimes misreported as an adjacent city, villiage or non-incorporated place, rather than the true township of residence. These reports led to inconsitent and inaccurate statistics for certain minor civil divisions (MCD). In order to improve the consistency and accuracy of the reported residence, a computer algorithm converted the the mothers' addresses to geographic coordinates for each birth record. This website uses these geocoded records as the primary determinate of the mothers' residence, instead of the residency recorded on the birth certificate. After 1989, birth statistics aggregated by county, city or township will reflect the corrected residence, and calculations will vary from those reported in the past.

Reliability: This website indicates statistical reliabiity of rates or percents by confidence intervals.

The true rate lies between the lower and upper bounds of the interval with 95% statistical confidence. If the confidence interval is large for a single-year comparison, it is suggested that you use the three-year or five-year moving average rates. Use the "period" list box to adjust the averaging method. For purposes of standards of reliability or precision, certain MCD statistics are only provided as three or five-year averages.

Poverty: This website uses an SES indicator based on the US census tract poverty level, proposed and discussed at the Public Health Disparities Geocoding Project. The method equates census tracts to large neighborhoods, and assumes that each person living in a given tract is approximately of the same economic class. The economic class is assumed to be correlated with the number of persons living below the poverty line in a tract. If 20% or more of the persons living in a tract are living below the poverty line, then that tract is considered a poverty area in US Census reports (for example, see Areas with Concentrated Poverty, 2000 and 2010). Therefore, those living in tracts where 20% of the persons are below the poverty line, are considered to be the poorest economic class. Those living in tracts where less than 20% of the persons live below the poverty line are considered to have more economic resources--either by employment, community services or better access to care.

The percent of persons living below the poverty line per census tract in 1990-1999 was estimated from the 1990 census. Similarly, the census tract poverty for 2000-2009 was estimated from the 2000 census. For 2010-2022, percent poverty is estimated from the 2007-2011 American Community Survey. Sudden shifts in the distribution around census years are indicative of updates to the poverty estimates, rather than sudden shifts in the poverty distribution.

If you have questions or comments about this web site, please contact Glenn Radford, by e-mail or by phone at (517) 335-9075.