With this decade’s redistricting cycle now in the books, it’s time for a complete refresh of one of Daily Kos Elections’ most frequently consulted resources: our spreadsheet of the overlaps between the nation's congressional districts and its media markets.
In the U.S., there are 210 television media markets—or more formally “designated market areas” (DMAs)—that are defined by Nielsen Media Research, which measures viewership. In each DMA, viewers can expect to see the same broadcast television stations, which makes them useful groupings for advertisers.
These media markets don’t have direct electoral relevance since of course they don’t elect their own representatives. But they do still play an important role in our understanding of politics because they’re the units by which candidates, PACs, and parties purchase broadcast television ads. And despite today’s fractured media environment, TV spots remain one of the most critical tools of any campaign, and in most competitive races, a campaign’s biggest expense.
Candidates of course have increasingly come to rely on digital advertising and social media outreach, and especially in smaller races, the best bang for the buck often still comes via old-fashioned, in-person get-out-the-vote operations. But in a statewide race or even most U.S. House races, this type of in-person work is difficult to do at the necessary scale. Beyond that, television ads are effective because the people who are likeliest to be watching broadcast TV—older voters—are also often the electorate’s likeliest and most reliable voters. In particular, ads on “event television” (like major live sporting events) are an easy way to reach a large audience and are especially coveted by advertisers.
A big part of why media markets are of particular interest to us at Daily Kos Elections is that when election season is in full swing, you’ll often see press releases—like this one from the pro-Democratic House Majority PAC—that a particular party committee or super PAC has booked TV time in a particular market or markets. The implications of such reservations may be clear to the inner circle of campaign professionals, but for the rest of us, how can we know which actual districts are affected?
To find out, you’ll need to know which congressional districts overlap the media market in question, which is precisely what our new spreadsheet details. From there, if you know which races are competitive, you can infer which actual House contests are being targeted—albeit with some wrinkles and caveats.
Let’s look at a hypothetical example: Suppose you see a story about a $1 million reservation by one of the major party committees or super PACs—like the DCCC or the aforementioned House Majority PAC—in the Detroit media market. The first step to figuring out which actual race or races this money is aimed at would be to pop open the tab of our spreadsheet that lists every market and the districts contained partly or entirely within each one.
Scrolling down to the Detroit DMA, you’ll see there are quite a few possibilities, as highlighted in the map at right: Michigan’s 5th, 6th, 7th, 9th, 10th, 11th, 12th, and 13th could all be targets. This large number makes sense given that 5 million people live within the market—which is much larger than the city itself—and each district is home to about 775,000 people. (You’ll also notice that all of these districts are in the state of Michigan; however, many media markets cross state lines, so that’s something to be aware of in general.)
We’ll then want to ask which seats are actually competitive, or potentially so. We can do this in a variety of ways. One helpful tool is Daily Kos Elections’ guide to third-party spending by the biggest groups involved in House races on both sides, which narrows the list down to just the 7th and 10th congressional districts. We can confirm this by looking at Daily Kos Elections’ calculations of the results of the 2020 presidential election for the new, post-redistricting districts, which show that both the 7th and 10th were very evenly divided according to this metric. (By contrast, the 6th, 11th, 12th, and 13th are all solidly Democratic, while the 5th and 9th are safely red.)
Next we’ll want to flip to the adjacent tab, which displays the same information but in reverse: It shows which markets make up each district. We can jump down to the section starting with Michigan’s 5th, which numerically is the first district that includes a piece of the Detroit market, as you can see in the excerpt to the right.
Focusing on our two likely districts, the 7th, you’ll see, overlaps with three different markets—and the largest is not Detroit. Rather it’s centered around the state capital of Lansing, where around 60% of the district’s residents live. If you wanted to make sure every voter in the district can see your ads, therefore, you’d almost certainly have to book time in both Detroit and Lansing. (You might however, skip Flint, since only a small portion of 7th District voters live there. In fact, most Flint residents live in other districts, so you’d likely be wasting a lot of ad dollars on viewers who can’t even vote in your race—an issue we’ll come back to.)
In our hypothetical example, though, we only have a reservation in Detroit. That makes it a lot more likely that it’s targeted toward the 10th District, which is an open Democratic swing seat centered in suburban Macomb County. This is a compact district with no rural components, placing it entirely within the Detroit media market.
In practice, though, it’s rare to see a well-funded super PAC or party committee announce a reservation in a single media market. When, for instance, the House Majority PAC, which is the largest super PAC involved in House races on the Democratic side, issued its press release in March that we linked above, it detailed $86 million in fall TV bookings, including four different Michigan markets all at once. It’s therefore eminently possible—in fact, likely—that some of HMP’s Detroit money is for the 7th, too.
That brings us to another point: All of these reservations are entirely fungible, meaning they can be used for any applicable districts. Indeed, priorities can and often do change as races become either more or less competitive. The only point at which money gets locked in for a specific contest is once an ad is actually run.
There’s another practical use for our database as well. Small donors who are concerned with making sure that their contributions in House races will be used most effectively can use this data to check which races offer the most bang for the buck. In this case, "effective" means spending most of your money on reaching people who can actually vote for you and not spending your money reaching people who live in a different district or even a different state—though as we’ll see, this isn’t really a choice candidates get to make so much as it reflects the fortunes of geography.
We alluded to this with Flint above vis-a-vis Michigan’s 7th, but an extreme example of perhaps the nation’s least effective congressional district is New Jersey’s 3rd. This district is split between the Philadelphia and New York City markets, with about three-quarters in the former and a quarter in the latter. To reach all voters on TV, you’d need to advertise in both markets—and both are very expensive, with New York being the priciest of them all and Philly not far behind.
Together, these two markets include 30 million people across all or part of 44 different districts in five different states. New Jersey’s 3rd District makes up less than 3% of that total, so anyone going up on TV there would be spending tons of money on ads that would be irrelevant to very nearly all viewers. Fortunately for Democratic Rep. Andy Kim, who holds the district, Democrats made his seat several points bluer in redistricting this year, and Republicans don’t seem to be targeting him this time, so he may be able to avoid major outlays on television. This will, however, always be a costly seat to advertise in.
Conversely, the real bang for the buck tends to happen in the smaller markets where there are fewer eyeballs wasted and little spillover into surrounding districts, especially in the rare cases where a single media market overlaps closely with a single congressional district. A good example is Oregon’s 4th District, a Democratic-held open seat shown at right: 96% of its population is in the Eugene market, while 89% of people who live in the Eugene DMA also live in the 4th District. Advertising on TV here can therefore be very effective, especially since prices in Eugene, which is the 113th-largest market in the country, are quite moderate.
Interestingly, perhaps the most efficient House district in the nation is host to a rather unexpectedly competitive race. We’re talking about Alaska’s At-Large District, which covers the entire state and where Democratic Rep. Mary Peltola, the surprise winner of this summer’s special election, faces a rematch against the same Republican opponents. None of Alaska’s three media markets—Anchorage, Fairbanks, and Juneau—bleed across state lines because, well, there are no neighboring states, so consequently there are no wasted eyeballs. In fact, Alaska is unique among states in that it has over 100,000 residents who live so far out in the bush that they simply don’t live in any broadcast media market at all! (You’ll notice the white expanses in Alaska in the map at the top of this post.)
In addition to the above, our new spreadsheet also includes the same breakdown of media markets at the state level. This is useful for understanding which markets a statewide campaign, like a race for U.S. Senate or governor, might need to advertise in to reach all voters. Georgia, for instance, is covered by 11 different media markets, half of which are based around cities that are located outside the state, such as Tallahassee, Florida. Most of the Georgia-based DMAs also cross state lines, so in total, these 11 markets reach 17 million people compared to the 10.7 million who actually live in the state. It’s nowhere near as extreme as the New Jersey example above, but if you were to blanket the state of Georgia, some 37% of viewers would be non-Georgians.
Finally, there’s a related Daily Kos Elections spreadsheet involving our nation’s media markets that may be of interest to you: our database of presidential elections broken down by media market. This, of course, isn’t affected by redistricting—Nielsen does occasionally make small changes to its map of markets every few years, but these tend to be nips and tucks rather than substantive remodeling—but we’ve made some recent updates since we introduced this spreadsheet several years ago.
In particular there’s been an additional presidential election since then, so we’ve added the 2020 results as you can see in the excerpt just below. We’ve also gone a bit further back, adding additional historical elections, so this chart now covers the full range from 1960 to 2020.
For the two most recent presidential contests, we’ve further broken down each media market by its state sub-parts since again, many markets cross state lines. This data is especially helpful for explaining which markets different statewide candidates or campaigns might target, and the differing messages they might use. In fact, one particularly compelling recent example came just this summer during the fight against the GOP-backed measure in Kansas to remove the right to an abortion from the state constitution.
In the Kansas City media market, Joe Biden won the portion inside the state of Kansas 53-45, so opponents of the measure ran ads specifically addressing abortion rights. In contrast, in the conservative Wichita market Donald Trump prevailed by a wide 65-33 margin. There opponents didn’t mention the word abortion at all and instead described the amendment as one that would “interfere with private medical decisions.” This bifurcated strategy paid off: The effort went down in a landslide 59-41 defeat.
Note: DMAs are typically made up of whole counties, but Nielsen does split eight counties (out of more than 3,000 total) between markets. In such cases, however, the large majority of a split county is usually found in one market. For our purposes, in both the congressional district spreadsheet and the presidential results by market sheet we just treat the entire county as belonging to that one market.
As an example, Oneida County, New York, is one of those counties; we treat all of Oneida as being in the Utica market, although the very westernmost parts of that county are in the nearby Syracuse market. The thorniest case may be the small Palm Springs media market carved out of the eastern part of Riverside County, California. Rather than trying to unpack Riverside County at the precinct level, you’ll notice that when we refer here to the “Los Angeles” market, we’re referring to the “Los Angeles and Palm Springs” markets collectively.
