The Center for Health Statistics has developed a system to calculate preliminary teen pregnancy rates for 10-17, 15-17, and 15-19-year-olds at the state and county level.
Preliminary 12-Month Moving Total:
The 12-month moving total is the sum of monthly counts of teen pregnancies to each age group of Oregon residents (births and induced abortions* during the previous 12-month period.)**
Example:
2010 2010 2011
J F M A M J J A S O N D J F M A M J J A S O N D J
| Feb10 - Jan11 |
| Mar10 - Feb11 |
| Apr10 - Mar11 |
...
| Feb11 - Jan12 |
Preliminary Rolling Rate:
The pregnancy rate per 1,000 females within each age category is calculated by dividing the 12-month moving total pregnancies by the most recent population estimate for Oregon females, multiplied by 1,000. During the year, the data are under constant revision.
Population Estimates:
The most current population estimates will be used, and replaced when new estimates are available. Population data by sex and age are typically available in April following the estimate year. Because of this, up to ten months of the current year's rates will be calculated using the previous year's population estimates. Teen pregnancy rates will be affected in counties with rapidly changing population estimates for teen females. Population estimates are provided by the
Population Research Center at Portland State University.
YTD Pregnancies:
Year-to-date (YTD) pregnancies are the sum of Oregon resident births and abortions as they are reported and updated quarterly to the Center for Health Statistics. The YTD figure is the actual number of pregnancies reported for the specific calendar year.
Preliminary and Final Rates:
Preliminary rates are undergoing final editing procedures, and may result in occasional and minor changes. Please label data as provisional or preliminary when reporting. Final rates for past years will not change and have been published in various vital statistics publications.
* For all tables associated with this project, abortion is defined as an induced termination of pregnancy, and does not include spontaneous abortions, also known as miscarriages, fetal demises, or fetal deaths.
** Rates and counts in counties where residents typically travel to other states to obtain medical services will reduce counts and rates until data are received from other states. This typically occurs a few months before the end of a calendar year. The reporting of abortions to the Center for Health Statistics is often delayed, which will also reduce counts and rates until the data are received. In addition, some states (i.e. California) do not report induced terminations of pregnancy of out-of-state residents to other states, which likely results in reduced counts for some counties.