Understanding what “underwater” means in polling mechanics cuts through a lot of political spin.
When CNN’s data team break down graphics like that, they are tracking net approval—the direct subtraction of disapproval from approval.
Anyone who pays much attention to social media knows that depending on the algorithm that determines your feed, you might get all sorts of political news tailored to fit your inclinations. One of the things that I get in my feed is CNN clips showing huge disparities in polling results. For instance, this morning I was looking at one that showed Trump on a 56-point swing. Going to 19 points underwater. I got to thinking what exactly does that mean?
Let’s also keep in mind that they love picking out the juiciest fraction of the polling results. 19 points underwater doesn’t mean he’s 19 points underwater across the board unless they explicitly say so. Oftentimes like the clip I was watching it’s rural voters which was bedrock Trump voters 2 years ago. So a 56 point swing is massive but I thought let’s go through this and explain it so that everybody is on the same page.
Net Approval vs. Absolute Percentages
It helps to break down how a candidate shifts from +37 to -19 in net numbers:
+37 Net Approval (Above Water): A politician is widely trusted on an issue. For instance, if 63% approve and 26% disapprove (63 - 26 = +37).
-19 Net Approval (Underwater): The ratio flips. If 36% approve and 55% disapprove (36 - 55 = -19).
NET APPROVAL SCALE
[ +37 ] =============> High Trust (Approve > Disapprove)
[ 0 ] ------------- Neutral Baseline
[ -19 ] =======> "Underwater" (Disapprove > Approve)
Breaking Down the 56-Point Net Swing
When a poll shows a drop from +37 to -19, it represents a 56-point net swing. That dramatic movement usually happens due to two primary polling factors:
Direct Mind Shares (Decided Voters Switching): Voters who previously approved of a figure’s handling of an issue shift directly into the disapproval column. Because every voter moving from “Approve” to “Disapprove” subtracts two points from the net gap (losing one positive point and adding one negative point), a relatively small group of flipping voters creates a massive visual gap on television graphics.
Undecided Movement: Voters who were previously on the fence (”Neither” or “Don’t Know”) break heavily toward the negative side as economic pressures escalate.
Why Network Graphics Use Net Margins
Cable networks use net numbers (”+37” or “-19”) because a single signed integer summarizes a complex split-percentage breakdown instantly for viewers on screen.
However, looking strictly at the net number without checking the raw underlying approval percentage can obscure key details—such as whether a candidate’s base is actively abandoning them, or if neutral swing voters are simply tilting negative.
For a visual breakdown of how data journalists present these net approval swings, you can watch CNN’s analysis of Trump’s inflation approval ratings.
This segment provides direct context on how network pollsters calculate net approval swings and present economic voter shifts.