Finding sources of data for computational, mathematical, or statistical modeling studies: free online data

[In this module we discuss methods for finding free sources of online data. We present examples of climate, population, and socio-economic data from a variety of online sources.  Other sources of potentially useful data are also discussed.  The data sources described here are by no means an exhaustive list of free online data that might be useful to use in a computational, statistical, or mathematical modeling study.] free Contents

Also, you need to be aware that free online sources of data should be properly cited in any report or paper related to your research.  In many cases, the data contained in the links given here represent *many* years of work to compile.


There are lots of different sources of free epidemiological, population data, climate data, etc available online, but sometimes it takes quite a bit of persistent patience (and quite a bit of luck) to find it on the Internet.

In this module we’ll be discussing how to find sources of online data, and give examples of some sources of data that can provide a rich source of ideas for statistical, computational, or mathematical modeling research projects.

Before we move on, let me stress that once you find a source of data online, immediately copy and paste the URL and put it into a file in your working directory (for instance, a README text file) with a little note about what data you found at that website, and the date you accessed it.  Also bookmark the page.  If you don’t do those two things, I *guarantee* that you will at some point regret that you didn’t.  Taking the time to develop good habits now at automatically documenting your sources of information as you find them is really important to your future career success.

Example of finding data on the web: smoking data


When trying to find data, the Google search engine is your best friend.  For instance, as a simple example, if I wanted to find smoking data by state, I would probably first try the search term

smoking historical data by state

When I did this search, a website near the top of the list that popped up was Data&Statistics CDC webpage for smoking and tobacco use.  Looking at that page reveals that there is all kinds of goodies related to tobacco use data.

But what if we wanted only Excel files (because I’m not a masochist and I don’t want to go through the work of transcribing by hand all the data that might be on a webpage if I don’t have to). To do that we can use the Advanced Search option in Google. Scroll down to the bottom of the Google search results for our search term above, and click on the Advanced Search option.  Then click on file type->Microsoft Excel, then click on the Advanced Search button.  This particular search didn’t seem to uncover anything that immediately looks promising. So maybe I can then try the search term

smoking data by year by state filetype:xls

This seems to produce some more hopeful results.

I could also try searching for smoking data by state for specific years.  My main point that I’m trying to make here is that using some creativity in searching for data can turn up some interesting data sources; don’t just give up because your first couple of search attempts yielded nothing.

If you don’t find anything after an hour or two of searching, then you may have to resort to extracting data from plots in published papers. Coming up with search terms that maximize your chances of hitting a jackpot of free data is a learned skill that you will find you get better at the more you do it.

When searching for a time series of data, good terms to include in your search are things like “data”, “historical”, “by year”, “by month”, etc. Over the years I have collected together sources of online data that have been useful for all kinds of different things.

Let’s take for example climate data; the ability to get a time series for temperature or humidity or precipitation for a location is applicable to a wide range of analyses.  I’ve used climate data in all kinds of different epidemiological studies, and also in some physics analyses I’ve done recently.  Climate data would also be a useful addition to studies of the dynamics in animal population, and/or in studies of temporal dynamics in vegetation or crops.

Climate Data


Adding potential climate effects to disease or animal population dynamic models can be an interesting way to expand the model, and is done surprisingly rarely (and thus there is a lot of low-hanging fruit for potential research topics).

To get a time series of climate data by month for pretty much any location in the world, first search for an international airport near that location, and get its three letter code (for example, the three letter code for the Phoenix airport is PHX).  For instance, say I wanted to examine the time series of temperature in Port au Prince in Haiti.  I would use the Google search term

port au prince haiti airport code

Google immediately replies that the airport code is PAP.

Now, the Weather Underground website provides the daily time series of temperature, precipitation, humidity, etc for virtually every single international airport in the world, often going back quite a few years (I think the longest time series I’ve found from that website go back to the 1940′s for some locations).

The data is derived from data from the National Oceanic and Atmospheric Administration’s (NOAA) National Climate Data Center (NCDC).

To access this data for a particular year and a particular airport, use a URL of  the form where YYY is where you would put the three letter airport code, and XXXX is the year. Here is the weather data for Port au Prince for 2007.

I can easily copy and paste this data into a text file that I could read into Excel, Matlab, R, etc.  If I wanted to add data for other years, I would just make the changes to the URL to get that data, then copy and paste it too into my text file.

If you wanted weather data for multiple locations for multiple years, it might be worth your time (if you are computationally adept) to write a Perl or Ruby script to download the data (writing such a script is way beyond the level of the discussion here, but I might cover writing such scripts as a topic in a future AML610 course at ASU, in which case the information will appear as a Module on this website if you are interested in learning more).

The Unix utility wget (curl on a Mac) can also be used to download data from a URL.

If you want to study long-term climate trends (or combine that information with a study of long-term trends in disease or population dynamics), the NOAA website makes available monthly temperature, precipitation and drought index time series on their “Climate at a Glance” website, going back to 1895(!).  You can break it down by state, and can get moving averages of the data.

The US Centers for Disease Control (CDC) also maintains a database of daily weather and air quality data that can be downloaded at the county level from this page.

You can also get daily time series of air pollutants for cities and counties in the US from the Environmental Protection Agency (EPA) The GeoData website also makes available time series for climate variables for locations across the world.

Another way to find climate data for any location in the world is to access it directly from the NOAA National Climate Data Center website.  A full list of stations with their World Metreological Organization (WMO) ID, latitude, longitude, and dates of operation can be found here.  The USAF number of is the WMO id.

Another nice lookup tool for the WMO id of stations in states or countries can be found here. And also here.

Once you have the WMO id of the station that is closest to the location of interest, you can go to the NCDC website which has time series of WMO station data going back to 1901 in some cases.  Click on the year of interest, and (if the WMO station you identified as being close to your location has data for that year) you can download the file for that year (the filename begins with the WMO station ID).

The file is not in a nice format for reading in, so the NCDC kindly has supplied a java script called for parsing the files.   Downloading climate data directly from the NOAA NCDC website can be a rather complicated process, thus I only recommend doing it if you have not been able to access the same data (in a much nicer format) from the websites described above; cases where this might happen is if there is no major airport close to the location of interest.

US Census Data


The US census keeps track of the economy and the population socioeconomic and educational demographics, and is a very rich source of data that is relevant to many different epidemiological/sociological/etc studies.

This website is a nice source for Excel files that have a lot of population data going back at least 10 years, including poverty, population, unemployment, income, and educational levels by county and state.

Note that counties all have a unique 5 digit code called the Federal Information Processing Standard (FIPS) code, the first two digits of which are the state code, and the last three digits are the county code.  The CDC maintains files that give a cross-reference between zip code and FIPS code. The Census Bureau provides a look up file for FIPS code to state and county.

Detailed population estimates (often by age, sex, and race) over time can be found here.

You can also download the census QuickFacts database containing data about population, age structure, income, poverty, and household size at the state and county level.

The National Cancer Institute maintains a database of population in 1 year age increments in counties in the US. The NCI also maintains databases of county level socioeconomic and demographic data.

NCI also has expected survival tables.

Current census information, including information on housing units, is available here.

Information about housing has changed over the past century is available here.

Poverty rate information is available from the Census Bureau here.

Marriage and divorce rates by state over time are available from the CDC.

GINI inequality indices are available from the Census Bureau by state, and nationally.

Vital statistics (birth rates, etc) can be obtained from the CDC VitalStats website.

Median household income is available from the Census Bureau.

Employment data by year is available from the Bureau of Labor Statistics.

The Minnesota Population Center at the University of Minnesota maintains a richly detailed database of US population information, some of it going back to the 1800′s.  You need to sign up for an account, but it is free to do so.  Once you have an account, you can login and go to this page to search for and download data sets.  Be aware that when requesting an account, you have to promise to use the data for good, not evil.  If you have plans to use your mathematical and data analysis skills for world domination, look elsewhere for your data…

Stock Market Data

Daily stock market data going back several years can be obtained from Yahoo Finance.  Use a URL of the form<stock ID>   where you put in the stock ID of interest.  For instance, HSY is the stock ID of the Hershey company.  Other free sources of stock data are discussed on this page

Schofield England Vital Statistics Data: 16th to 19th century


The book Population History of England, 1541-1871 by RS Schofield contains a CD rom with baptism, marriage and burial data from over 400 parishes in England (the data does not include parishes in London). I am using this data in my research, and I spent a significant amount of time collating the Schofield data and meshing it with climate data.  If you are interested in using this data for a project, please talk to me. I’ve summarized the data in the file summary_schofield_parish_data.txt.gz (you need to gunzip the file before you can use it) that contains the number of marriages, baptisms and burials by year and month in the various parishes, along with a data quality code (0 if no issues, 1 otherwise) that indicates if Schofield had flagged the data for that particular month as being incomplete.

The file also contains the x and y position of the parish (in some mysterious units, and relative to some mysterious x=0, y=0 benchmark… however, the position info is useful for determination of which parishes are neighbouring each other), and also the population of the parish in the first census of the 19th century.

For each parish I’ve added in the average monthly temperatures from 1659 onwards, and precipitation from 1766 onwards, in Central England from data obtained from the UK Met office website.  If using this data,  Schofield’s book must be cited in addition to this paper and the papers on this website related to the climate data. Be aware when working with this file that there are different date ranges of data for each parish.

Economic Data

GDP economy background concept

Economic data by state or county in the US can be found here

Data on monthly retail sales in the US are available here and here, and other reports are available here.

State GDP data can be found at the Bureau of Economic Analysis website.

General Social Survey


From Wikipedia: The General Social Survey (GSS) is a sociological survey used to collect data on demographic characteristics and attitudes of residents of the United States. The survey is conducted face-to-face with an in-person interview by the National Opinion Research Center at the University of Chicago, of a randomly selected sample of adults (18+) who are not institutionalized. The survey was conducted every year from 1972 to 1994 (except in 1979, 1981, and 1992). Since 1994, it has been conducted every other year. The survey takes about 90 minutes to administer. As of 2010 28 national samples with 55,087 respondents and 5,417 variables had been collected. The data collected about this survey includes both demographic information and respondent’s opinions on matters ranging from government spending to the state of race relations to the existence and nature of God. Because of the wide range of topics covered, and the comprehensive gathering of demographic information, survey results allow social scientists to correlate demographic factors like age, race, gender, and urban/rural upbringing with beliefs, and thereby determine whether, for example, an average middle-aged black male respondent would be more or less likely to move to a different U.S. state for economic reasons than a similarly situated white female respondent; or whether a highly educated person with a rural upbringing is more likely to believe in a transcendent God than a person with an urban upbringing and only a high-school education.

GSS results are freely made available to interested parties over the internet, and are widely used in sociological research.

The data are generally available in formats designed for statistical programs (e.g.,R/SAS/SPSS/Stata).

The GSS was recently linked to the National Death Index. This freely available dataset allows researchers to explore the association between variables in the General Social Survey and human longevity. For instance, it is possible to explore the association between happiness and life expectancy.[1] The dataset and codebook are available for download by the public.

Education Data


Dropout rates by state can be obtained from the National Center for Education Statistics.

The US Office of Juvenile Justice and Delinquency Program provides data on high school graduation rates.

Education expenditures by state can also be obtained from NCES, along with literacy rate estimates by state.

Educational attainment by state by year is available from the Pell Institute.

The number of educational institutions in the US is available from the National Center for Education Statistics.

The Statemaster website also provides state and country level education statistics, along with statistics related to pretty much every other topic under the sun.

Agricultural Data (animals and crops)


The USDA every few years does a census of farms and makes data available online related to farm economy, crops, and livestock. This data is usually available at the county level.

Location, GIS Data, etc


Data on latitude, longitude and population for cities all over the world can be obtained from the World Atlas website.  This data is useful for models or analyses that have a geospatial component.

The GeoNames website also has files you can download with latitude, longitude, population, and other information for towns and cities all over the world.

From NOAA you can get the elevation of points on the earth on a grid of latitude and longitude in 1″ increments. (approx 30m resolution)

From NASA, you can get data from the Shuttle Radar Topography Mission, that mapped elevations on the Earth in a grid of 1″, 3″ and 30″ increments.  The website returns files in STRM .hgt format.  This webpage provides a C++ program to convert the hgt format to csv (lat, long, elev).

The Google EarthEngine website has various data sets available related to surface reflectance, satellite composite images, etc for most places on Earth.

This R script gives an example of code to obtain the latitude and longitude of nearly all towns and cities on earth.

Change in Earth due to human impact


NASA, US Geological Survey, Google and TIME have collaborated and recently released the Timelapse project that provides time lapse satellite imagery of the Earth from 1984 to present.  The effect of climate, population change, deforestation, etc can clearly be seen in many places.

Disease and mortality data


The CDC Wonder website maintains databases related to births/deaths/mortality/disease/etc in the US.  It is a goldmine of data!

The Compressed Mortality database allows you to design your own customized data sets of mortality time series data where you can sort data by age group/year/month/county/state/cause of death/etc/etc/etc.

The CDC Web Based Injury Statistics Query and Reporting System (WISQARS) is an interactive database system that provides customized reports of injury-related data, for both fatal and non-fatal events, plus violent deaths.

Data on the incidence of STDS by age/gender/state/year/etc can be found here.

The CDC also has a website that allows you to access their Morbidity and Mortality Weekly Reports going back to 1996.  The tables contain the incidence data for reportable diseases (that is to say, diseases that the CDC have identified as posing significant threats to public health, and thus physicians in the US must report cases to the CDC). The data are broken down by disease, state, and week.  Note that these are not mortality data… the data are the number of people who got sick in a given week and in a given state with a particular disease.

The CDC also makes its mortality data by age group, and also for pneumonia and influenza, available by week for 122 major cities in the US, going back to 1996.

Trends in teenage pregnancy rates are compiled by the Guttmacher Institute.

The CDC publishes weekly reports on the incidence of various influenza strains at the national and regional levels. The excel files containing the data, by geographic region can be found here (also has data on ILI surveillance).

Flu hospitalization rates by region, year, and age group are available here.  Vaccination coverage data is available here.

The US Department of Health and Human Services SAMHSA website makes available state-level estimates of illicit drug use, and tobacco and alcohol use.

Airline enplanement data


 Passenger enplanement data for all airports in the US by state and by year is available from the FAA.

The number of passengers by airport by month is available from the Bureau of Transportation Statistics.

The total number of passengers per month for all of US available from here.

Airport data is available from here.

Passenger and freight information by airport is available from here.

Point of origin and destination data by month from here and here.



There are no official databases that keep track of the number of firearms sold in the US.  However, the number of firearm background checks over time has been shown to be highly correlated to the number of firearms manufactured in the US over time.  Thus the monthly number of background checks by state can be used as a proxy for the number of firearms sold. A summary of firearm ownership by state can be found here.

The number of active concealed carry permits in each state has been estimated here.

The number of deaths due to firearms by county/month/year/age group/etc can be found in the CDC Wonder compressed mortality database for 1999-2010 by selecting ICD10 codes X72-74 X93-95 and Y22-24 in the advanced finder.

As of 2012, the ATF now releases information regarding the number of firearm seizures by state, the type of firearm, the age of the offender, what state the firearm originated in, and how long it took for the firearm to be used in a crime.

Since 2005 the TSA has been keeping monthly records of the number of firearms confiscated at airport security checkpoints at all airports in the US (back to 2002 apparently they only collected data for some airports).  This number has been growing over the past decade. Data before 2012 must be obtained from the TSA via a Freedom of Information Act request.  I know that the data prior to 2005 is unreliable from information given to me in a conversation with a person at the TSA who phoned me to ask for more information about my FOIA request for data.  A graphical summary of TSA confiscation data from 2002 to 2010 can be found on this page.

US murders 2007-2011 by weapon type. Murder by state by type of weapon used for 2011. Murder by state by type of weapon used for 2010. Murder by state by type of weapon used for 2009. Murder by state by type of weapon used for 2008 Murder by state by type of weapon used for 2007. Murder by state by type of weapon used for 2006. Murder by state by type of weapon used for 2005. Murder by state by type of weapon used for 2004 Murder by state by type of weapon used for 2003 (Table 20 pg 249) Weapon use and violent crime 1993-2001 Report on homicide trends from 1980 to 2010.

USA Today has compiled a list of mass killings in the US between 2006 to 2013, along with the weapon used, and type of killing (public, family, robbery/burglary, or “other”)

Crime data


The FBI maintains crime databases.

In addition, the City of Chicago maintains a database giving the details of all crimes committed in the city going back to 2001.

The Bureau of Justice Statistics maintains databases based on the National Crime Victim Survey. Note that there are other crime-related data goodies accessible in the links on the left hand side bar of that page. Like this.

The National Archive of Criminal Justice Data website has all kinds of reports, datasets, etc related to crime, drugs, alcohol, victimization, justice system, police, etc.  You need to set up an account to access the site, but signing up for one is free.

The Statemaster website provides a comparison of various crime-related statistics for countries around the world.



Voter turnout by state for various past elections can be found here.

The Census website maintains files on voting population by age and race. Also here.

Lots of information about past US federal elections, provided at the state and county level can be found at US Election Atlas.

The Center for American Women and Politics provides statistics on gender patterns in voting preferences in past elections.

The Pew Research Center collects and disseminates data on a wide variety of topics, including on past elections.

Data related to campaign contributions for past elections can be found here.

Data on peoples’ political viewpoints can be found at (note that you need to sign up for a free account to access the data.  Note that the data are likely significantly biased because it is a voluntary online survey, and is thus filled out a) only by people who have no problems with sharing quite personal information with others, b) the accuracies of the survey results relay on people being truthful, and c) people with access to a computer and are savvy enough to navigate an online survey (ie; the people filling out the survey will almost certainly be skewed to a younger population).

Exit poll data on past elections can be found at the Roper center of public opinion archives (you have to sign up for a free account to access the data).

Traffic Accidents


The National Highway Traffic Safety Administration maintains databases related to car crashes.

Lunar Phase Data


Various animals have their reproductive cycles tied to moon phase.  There are many people who believe that human behaviour is also affected by moon phase. NASA maintains a database of lunar phases by day over a 6000 year period. In the file full_moon_data.txt I have taken the NASA data and summarized it in a file that gives the moon phase for all days between 1700 to 2099.  The moon  phase is expressed as a fraction of the lunar synodic period (which has an average of 29.5 days) from the nearest full moon.  Thus this fraction goes between -0.5 to 0.5, where 0 means the day of the full moon, and -0.5 (or 0.5) means the day of the new moon.

Genomic data


The 1000 Genomes project is an international research effort to establish by far the most detailed catalog of human genetic variation.  Data from the project is made freely available from the project website.

GDELT database: global database of events, language and tone


The GDELT: Global Data on Events, Location and Tone. Primarily set up by Kalev Leetaru at the University of Illinois it is literally a giant list: over 250m events in over 300 categories from riots and protests to diplomatic exchanges and peace appeals. Crucially, it contains latitude and longitude for every event – all of them are now geotagged to city level.

It’s based on on news media from AfricaNews, Agence France Presse, Associated Press Online, Associated Press Worldstream, BBC Monitoring, Christian Science Monitor, Facts on File, Foreign Broadcast Information Service, United Press International, and the Washington Post. They include “all national and international news coverage from the New York Times, all international and major US national stories from the Associated Press, and all national and international news from Google News with the exception of sports, entertainment, and strictly economic news.” It only goes back to 1979 now, but eventually it will include all events back to 1800.

Global Terrorism Database


Researchers at the University of Maryland have compiled and maintain a richly detailed database of all terrorist events across the world going back to 1970, called the Global Terrorism Database. Access to the database is free, but requires you to sign up for a subscription to the website.  


Google Trends is a service provided by Google that allows you to examine the temporal trends in Internet searches, by topic,  and even by country.  We used this data in an analysis of the effect of media stories on peoples’ Internet searches related to Ebola during the (almost non-existent) Ebola outbreak in the US in 2014.


The Mutual UFO Network (MUFON) maintains a database of UFO sightings that can be indexed by date, location, etc.

Leave a Reply