UMD Global CTIS Map

A live map of the world showing the percentage values for COVID-19-like symptoms, mask wearing, vaccine acceptance and more based on responses to The Global COVID-19 Trends and Impact Survey.

Go to our map

UMD Global CTIS Open Data API

An open API to access aggregated Global COVID-19 Trends and Impact Survey data.

Go to our API

UMD Global CTIS Microdata Repository

Data repository for daily individual survey responses with survey variables and weights.

Go to microdata repo

UMD Global CTIS Contingency Tables

Contingency tables providing more granular breakdows of survey reponses such as vaccine update and acceptance.

Go to Contingency Tables


The University of Maryland Social Data Science Center Global COVID-19 Trends and Impact Survey, in partnership with Facebook is a partnership between Facebook and academic institutions. The survey is available in 56 languages. A representative sample of Facebook users is invited on a daily basis to report on topics including, for example, symptoms, social distancing behavior, vaccine acceptance, mental health issues, and financial constraints. Facebook provides weights to reduce nonresponse and coverage bias. Country and region-level statistics are published daily via public API and dashboards, and microdata is available for researchers via data use agreements. Over half a million responses are collected daily.

Data for the United States is not included in the Global COVID-19 Trends and Impact Survey but is available at

Overview of Survey Design:Partnering with Facebook on a University-based Rapid Turn-around Global Survey Detailed Methodology:Weights and Methodology Brief for The Global COVID-19 Trends and Impact Survey
Survey Limitations:Survey limitations page on Open Data API website

What's new

Oct 15, 2021
  • On October 7 EST at 5 AM, we deployed Wave 12 pretest of the Global COVID-19 Trends and Impact Survey (CTIS). Please find the codebook and PDF of the instrument. This pretest of the Wave 12 survey is largely experimental and tested on 20% of the daily sample in nine test countries (Germany, France, Mexico, India, Indonesia, Japan, Australia, South Africa, and Vietnam) with 20 languages provided (Arabic, Bengali, German, English (UK), English (US), Spanish (LATAM), Persian/Farsi, French, Gujarati, Hindi, Bahasa Indonesia, Italian, Japanese, Marathi, Polish, Romanian, Russian, Turkish, Vietnamese, Chinese (simplified)). All respondents outside of the nine test countries and 80% of the respondents within those test countries will continue to see the current instrument in Wave 11. After collecting data for several weeks and analyzing the results, we will deploy a finalized version of Wave 12 to all respondents.

  • June 28, 2021
  • The sample size decline issue is resolved. There was a bug in the in-app web browser in the Android version of the Facebook app released on June 17. The issue has been fixed in the version of the Facebook app released on June 24. The issue caused a ~50% decrease in total response volume across the CMU and UMD, but as of June 26, 89.5% of the initial decrease in total response volume has been recovered. We expect to see the total response volume continue to recover as Android users continue to update to the latest Facebook app.

  • June 25, 2021
  • We have uncovered a decline in sample size since 06/17/2021. A preliminary analysis suggests that a technical problem during the survey delivery process affects respondents on Android devices, causing lower response rates in that group. Engineering teams are currently investigating the issue to make a fix in the next day or two. Until then, we expect the sample size to remain lower. Please be aware that the issue primarily affects Android users, and it may result in a systematic bias in the survey sample. This may result in unexpected shifts in survey estimates, so if you're using the survey data in a real-time dashboard or analysis system, you should carefully check recent data for unexpected changes.

  • June 7, 2021
  • On 06/07/2021, we reverted to the Wave 10 version of the symptom section questions to prevent continued discontinuity. Personal symptom questions (B1, B1b, B2) are now displayed before community symptom questions (B3, B4). The question stem in B1 also changed back to "In the last 24 hours, have you had any of the following?" However, the symptoms 'changes to sleep' and 'eye pain' remain dropped from B1. Please see the updated survey instrument for more information. There is also a blog post about the wave 10 and wave 11 CLI trend break here.

  • June 3, 2021
  • A new version of the survey (V11) was launched on 05/20/2021. This was a major revision of the survey, and as a result of these revisions, we have observed discontinuities in our covid (COVID-like illness) and flu (influenza-like illness) aggregate indicators that are reported in our API.

    To test the effects of the changes to the survey, 20% of respondents have been receiving the old version of the survey (V10) and 80% have been receiving the new version of the survey (V11) since its launch on 05/20/2021. To enable monitoring of the observed discontinuities in the existing covid and flu aggregate indicators, we will be adding two new aggregate indicators to the API,which are calculated using the same methodology. These new indicators (cli and ili) will be calculated using the 80% of respondents receiving V11 while the existing indicators (covid and flu) will be changed to be calculated using only the 20% of respondents receiving V10. The new and existing indicators will be backfilled to 05/20/2021 and will continue to be reported in this manner until at least 06/17/21.

    We are continuing analyses of these discontinuities, but in the interim, we encourage users of the aggregate data to re-pull the backfilled “covid” and “flu”indicators when they become available. To be notified when they are ready, please subscribe to our survey listserv. We encourage both users of the aggregate data as well as microdata users to use caution for comparing data collected after 05/20/2021 to data collected before 05/20/2021 for other indicators as well. We also encourage microdata users to use data from the 20% of the respondents who have been receiving the old version of the survey (V10) to evaluate the effects of the survey revisions for the survey questions used in their analyses.

  • May 20, 2021
  • A new version of the survey(V11) has been launched. Microdata starting from 2021-05-20 will have responses from additional questions. This version is a major revision to the instrument, please see survey instrument, codebook, and change summary for more information.

  • March 2, 2021
  • A new version of the survey(V10) has been launched. Microdata starting from 2021-03-02 will have responses from additional questions. Please see survey instrument for more information

  • February 6, 2021
  • A new version of the survey(V9) has been launched. Microdata starting from 2021-02-06 will have responses from additional questions.
  • UMD Researchers

    Frauke Kreuter


    Director of Joint Program in Survey Methodology

    Kathleen Stewart


    Director of the Center for Geospatial Information Science

    Data Engineering

    Zheng Liu

    Yao Li

    Visualization and API Development

    Yao Li

    Joe O'Brien

    Survey Design and Fielding

    Samantha Chiu

    Xiaoyi Deng

    Technical Support

    Anil Kommareddy