1. Tale of two polls: CBS News/YouGov roughly 4 years apart - 45-37 Clinton 8/30-9/2 2016; 49-43 Biden 8/4-8/7 2020

2. Here are the competing crosstabs. 2016: https://www.scribd.com/document/322977191/CBS-News-Battleground-Tracker-Pennsylvania-September-4#from_embed and 2020: https://drive.google.com/file/d/1CFgA4CjSVJSJYPxfLsQj6BUWuXo_YHd7/view A few things stand out.

3. White vote by education level spelled out in 2020 crosstabs, not in 2016. So can't compare there.

4. Should note that these are Pennsylvania polls in each instance (omission from first tweet)

Additionally, the 2016 poll included 2 third-party candidates, Gary Johnson (6%) and Jill Stein (2%), by name. 2020 just Biden v Trump.

5. Including third-party candidates by name generally inflates their eventual totals (Johnson and Stein got 2.4 & .8 in PA, respectively)

6. I'm combining Johnson/Stein/Don't know/Someone else options into "other" for brevity here for both years. That includes those 4 categories for 2016, and just not sure/someone else for 2020

7. Probably the key difference, and *perhaps* good for Biden even though his lead in this poll (6) nominally lower than HRC's (8) last time ---

8. 2020: Biden 90-4 w/ Ds, Trump 90-6 w/ Rs, Biden 44-40 w/ indies. 2016: HRC 83-8 w/ Ds, Trump 75-6 w/Rs, Trump 35-33 w/ indies

9. Big difference w/ party ID: Trump had more room to grow in 2016 w/ more undecided Rs and had nominal lead w/ indies.

10. Trump realized that growth potential: 2016 exit poll indicated that Trump had slightly better party unity than HRC & won independents https://www.cnn.com/election/2016/results/exit-polls/pennsylvania/president

11. Now, Biden/Trump both have party unity, Biden nominal lead w/ indies

12. So Trump technically closer in this poll than he was in early Sept. 2016 poll, but perhaps not as many avenues to grow w/ fewer other/undecided voters, more party unity for both candidates, and Biden up (narrowly) w/ indies

P.S. you can see a similar dynamic comparing today's Wisconsin CBS News/YouGov w/ one from early October 2016. 2016 crosstabs: https://www.scribd.com/document/326944222/CBS-News-Battleground-Tracker-Wisconsin-Oct-9-2016#from_embed and 2020: https://drive.google.com/file/d/1HySmD4Wu_uSqXjyvK69R3Re9pJUXvEHm/view