Hello, my name is...
Dhrumil Mehta (he/him)
dhrumil.mehta@columbia.edu
@datadhrumil
@dmil
Highlights:
Currently
-
Associate Prof. @ Columbia Graduate School of Journalism
-
Visiting Associate Prof. @ Harvard Kennedy School
Previously
-
Database Journalist, Politics @ FiveThirtyEight
- Software Development Engineer @ Amazon
- Northwestern:
- BA in Philosophy + Minor in Cognitive Science
- MS in Computer Science
Database Journalist, Politics
Polls
Is polling becoming less accurate?
Is horserace polling becoming less accurate in the US?
Is horserace polling becoming less accurate in the US?
https://www.monmouth.edu/polling-institute/reports/monmouthpoll_ga_102820/
Title Text
Polling error tends to be correlated in a given election cycle
Is horserace polling becoming less accurate in the US?
Communicating Uncertainty
Interpreting Summary Statistics
What is included?
What is excluded?
Methodological choices / assumptions
Inferential Statistics
Parameters are numbers that summarize data for an entire population. Statistics are numbers that summarize data from a sample, i.e. some subset of the entire population.
- source: David Gurney
Remember "margin of error" is only the margin of sampling error. There are other sources of error as well.
Communicating Uncertainty
Communicating Uncertainty
Polls are not a crystal ball 🔮
- They are a "snapshot in time"
- They are a statistical sample
- Election polls are built upon assumptions of who will turn out to vote -- "likely voters".
They're one piece of information that can help you better understand state of a race.
Don't ignore them. But don't worship them.
Some journalists who talk about polls in US elections on Twitter
Ariel Edwards Levy - CNN (formerly HuffPost)
@aedwardslevy
G Elliott Morris - The Economist
@gelliottmorris
Lenny Bronner - Washington Post @lennybronner Nate Cohn - New York Times @Nate_Cohn Nate Silver - FiveThirtyEight @NateSilver538
Final thoughts
- When it comes to issue polling -- always look for as many polls as you can find on a particular topic. Start with a spreadsheet!
- When it comes to election polling -- follow the conversation that pollsters and aggregators are having. There are also important signals coming from academia and research centers, especially retroactively.
- To understand the quality of a particular pollster, pay attention to their historical track record of accuracy. Try to avoid building a story around a single poll.
- Beware of fake polls. Like all forms of misinformation, they're on a sliding scale of "fakeness".
dhrumil.mehta@columbia.edu
@datadhrumil
@dmil
