About PlainHealth

Last updated: June 23, 2026

Our Mission

PlainHealth exists because public health data should be genuinely public, not locked behind interfaces designed for statisticians. The CDC's WONDER database is one of the most valuable public health resources in the world, containing decades of mortality data that can inform everything from community health planning to individual risk awareness. But its 1990s-era interface makes it functionally inaccessible to the journalists, students, policymakers, and curious citizens who need it most.

We believe that mortality data collected at public expense belongs to the public in a form they can actually use. PlainHealth transforms raw CDC data into a modern, searchable format that makes it possible to explore causes of death by state, compare regional patterns, and track how mortality trends have changed over 19 years, without needing to navigate complex query interfaces or understand ICD-10 coding systems.

We present the data without editorializing, ranking, or implying value judgments. Our role is to make the data accessible and let users draw their own conclusions from the official government figures.

Our Data Sources

CDC/NCHS Mortality Data

PlainHealth draws from a single authoritative federal source, the National Center for Health Statistics (NCHS) Leading Causes of Death dataset, with age-adjusted rates from CDC WONDER:

• NCHS Leading Causes of Death Dataset (1999-2017) - Final mortality data with age-adjusted rates, published by the National Center for Health Statistics. It uses finalized death certificates and standardized cause-of-death coding, organized into the 10 leading causes. Available at data.cdc.gov.
• CDC WONDER, Underlying Cause of Death - The source of the age-adjusted rates, standardized to the year 2000 US standard population. Available at wonder.cdc.gov.

This provides a complete 19-year grid (1999-2017) covering deaths registered in all 50 states and the District of Columbia across the 10 leading causes of death, 9,690 records with no gaps. We use only finalized data, so the series does not yet cover the COVID-19 era; it will extend as CDC finalizes later years.

How We Process the Data

We download source files from the CDC's open data portal and process them through the following steps:

• Parsing and normalization: Source files from different time periods use different formats and field names. We normalize all records into a consistent schema with standardized state names, cause-of-death categories, and time periods.
• ICD-10 classification: Causes of death are organized using the International Classification of Diseases, 10th Revision (ICD-10) chapter system. This groups related causes (e.g., all heart-related deaths under "Diseases of the circulatory system") for meaningful comparison.
• Age-adjusted rate calculation: Age-adjusted rates use the year 2000 US standard population, enabling fair comparison between states with different age distributions. Without age adjustment, a state with an older population would appear to have higher mortality simply because older people die at higher rates.
• Suppressed data handling: CDC WONDER suppresses death counts under 10 for privacy protection. These appear as "Data not available" on PlainHealth, they are not zeros, and should not be interpreted as such.
• Trend computation: Multi-year trends are computed from the standardized data, showing how mortality rates have changed over time for each cause and geography.

Data Currency

PlainHealth displays the finalized NCHS Leading Causes of Death series, which runs 1999-2017. We use only finalized, age-adjusted data rather than provisional later years.

CDC final mortality data is typically published 2-3 years after the reference period. We extend PlainHealth when CDC finalizes additional years of the leading-cause, age-adjusted series.

Like all federal statistical programs, there is inherent lag between when deaths occur and when finalized data becomes publicly available. The most recent 1-2 years should always be treated as preliminary, figures may be revised upward as additional death certificates are processed.

Limitations & Disclaimers

PlainHealth is an informational resource. Mortality data should be interpreted with appropriate context and should not be used as a substitute for professional medical or public health guidance.

• Geographic aggregation: State-level data masks significant variation within states. Two states with identical age-adjusted mortality rates may have very different patterns across urban, suburban, and rural areas.
• Coarse cause rollup: The 10 leading-cause chapters are a deliberately broad grouping, not the full ICD-10 code set. At this level every state-cause-year cell clears CDC's privacy threshold, so the grid is complete with no suppressed values.
• Finalized scope: The series uses only finalized NCHS data and currently ends in 2017, so it does not cover the COVID-19 era. We extend it as CDC finalizes later years rather than showing provisional figures that may be revised.
• Cause-of-death coding: Death certificates list a single underlying cause of death, which may not capture the full picture for individuals with multiple contributing conditions. The shift from ICD-9 to ICD-10 in 1999 also affects historical comparability.

This site is for informational purposes only and does not provide medical advice. The data presented comes from government sources and is not a substitute for professional medical consultation. Always consult a qualified healthcare provider for medical decisions.

Contact

Questions, corrections, or feedback? Email us at hello@plainhealthdata.com.

We welcome:

• Questions about data sources or methodology
• Reports of apparent data errors or anomalies
• Suggestions for additional data or features
• Media and research inquiries

PlainHealth is an independent publisher of free, public-interest data drawn from official government datasets. For how these pages are produced and how to report an error, see our editorial & corrections policy.