Adjustments for Areas Impacted by Hurricanes Katrina and Rita

Hurricanes Katrina and Rita had a huge impact on the populations within Gulf Coast region for the second half of 2005. Katrina also significantly impacted the Louisiana Cancer Registry's ability to report data for that time period. In an effort to provide the most accurate and complete data and statistics possible, the SEER Program made several changes for the releases of data and statistics that include cases diagnosed in 2005.

SEER Research Database

Because of the impact on Louisiana's population for the July - December 2005 time period, SEER excluded Louisiana cases diagnosed for that six month time period. By definition, Louisiana cases for 2005 are only included in SEER's Research Database if they were diagnosed in the first half of 2005 (January - June). The Hurricane Katrina Impacted Louisiana Cases are provided with the data, but they are considered supplemental data and are not typically reported by SEER. In SEER*Stat, Louisiana cases are treated differently by session type:

  • For prevalence calculations and incidence-based mortality databases, all Louisiana cases are excluded for all years by default.
  • For multiple primary standardized incidence (and mortality) ratios, all Louisiana cases for all years are included.
  • For all other sessions, including incidence rates, survival, left-truncated life tables, frequencies, and case listings, SEER excludes Louisiana cases diagnosed for the six month period, July-December 2005, by default.

Katrina/Rita Population Adjustment

The US populations included with the data release have been adjusted for the population shifts due to hurricanes Katrina and Rita for 62 counties and parishes in Alabama, Mississippi, Louisiana, and Texas (See US Population Data for more information).

Once the populations were adjusted for the counties and parishes within the four states, the resulting total US population was lower than the July 1 total US population. The difference represents people displaced by the hurricanes who went to other parts of the US. A separate dummy state has been introduced that represents these people. It is labeled ”Hurricane Katrina/Rita Evacuees - Populations Only - 2005” and is included by default in rate calculations over the total US. There is no population adjustment for prevalence databases.

Statistical Reporting with the Population Adjustment

Using SEER Incidence Data

Although each incidence database distributed with SEER*Stat includes "<Katrina/Rita Population Adjustment>" in the name, these adjustments are only applicable to the SEER 18 Registries data, which includes Louisiana.

Using US Mortality Data

When SEER reports on the total US, populations for the dummy state created to represent the evacuees, ” Hurricane Katrina/Rita Evacuees - Populations Only - 2005”, are included in the analyses. Based on an analysis of Postal Service, ESRI data by the Los Angeles Times1, we know that the majority of those evacuees relocated to the following eight states: Texas, Arkansas, Louisiana, Mississippi, Alabama, Tennessee, Georgia, or Florida. When reported rates include those eight states, ” Hurricane Katrina/Rita Evacuees - Populations Only - 2005” are included in the analyses. If one or more of those states is excluded, then the evacuees are also excluded.

1 Where the Displaced Landed [Internet]. Los Angeles (CA): Los Angeles Times. 2005 Dec 12 [cited 2005 Dec 12]. Available from