Science and health
Are vaccines an effective tool to prevent disease?
Position tracked against: “Vaccines are an effective tool to prevent disease.”
How do chatbots’ citation patterns change over time?
Share of answers with a citation, each day.
GPT-5Claude Sonnet 5Gemini 3.5 FlashGrok 4.5Muse Spark 1.2
Position over time
Average position each day on one yes-or-no question (+1 yes, −1 no).
GPT-5Claude Sonnet 5Gemini 3.5 FlashGrok 4.5Muse Spark 1.2
Vaccines are an effective tool to prevent disease.
How often do chatbots cite external sources?
Share of answers with at least one link/citation.
Most-cited websites
Domains by number of citations.
who.intGovernment331
cdc.govGovernment202
merckmanuals.comEncyclopedias and reference37
hhs.govGovernment32
pmc.ncbi.nlm.nih.govAcademic30
asm.orgNonprofits and think tanks30
royalsociety.orgAcademic24
acsh.orgNonprofits and think tanks21
medlineplus.govGovernment20
healthdata.orgAcademic19
ourworldindata.orgData and tools16
commoncrawl.orgNonprofits and think tanks15
historyofvaccines.orgNonprofits and think tanks14
webmd.comCommercial content13
un.orgGovernment13
jamanetwork.comAcademic10
medscape.comNews and media8
aai.orgNonprofits and think tanks8
aap.orgNonprofits and think tanks7
gavi.orgNonprofits and think tanks7
What kinds of sources do chatbots use?
Share of each chatbot’s citations by type of publisher.
News and mediaEncyclopedias and referenceAcademicCommercial contentGovernmentNonprofits and think tanksCompaniesSocial media and videoBlogs and newslettersData and toolsNot yet classified
Which way the sources point
On yes-or-no questions, whether what each citation backs points to yes, to no, or neither.
Points to yesNeutral