One of the biggest areas of disagreement on the wall is its cost efficiency.

Republicans claim it will save us money by preventing the need to support illegal immigrants who enter the US, while Democrats argue the wall is just too expensive to ever be a cost efficient approach to addressing illegal immigration. I'm looking for hard numbers regarding this claim. Can we compare the potential costs to potential savings and figure out whether it has a positive ROI (return on investment)?

For now I'm trying to look at a few things:

  1. Long term costs after the wall is built (total construction cost, maintenance, repairs, staffing, etc.).
  2. To get an idea of potential economic benefit, if any, after being built as a result of the wall doing its intended job.
  3. Perhaps, if applicable, how many years it would take to recoup the cost of building the wall based off of money saved in the previous point.

On one side I'm looking for the most accurate number on cost savings on lowering illegal immigration. What does the government estimate the cost of illegal immigration to be currently? What is the economic gain or loss per year on preventing illegal immigrants from entering the US? What are the numbers if we presume the wall hypothetically stops 100% of Mexican non-overstay illegal immigration? It's unlikely any action will stop 100% of illegal immigration, so can you cite any source(s) that give a more reasonable percentage expected to be stopped by the wall if built and what that equates to in potential costs/savings?

On the other side of the calculation, what would be the cost of maintaining the wall, i.e. manning it, repairing damage to it, and generally keeping the wall functional after it is built? How would this maintenance cost compare to the economic impact on the US citizens in stopping some illegal immigration?

Since we're looking at long term costs here, the original cost of building the wall is only relevant in the lost opportunity cost (in layman's terms, what benefit would we get out of the money if we spent it elsewhere). You are welcome to try to include opportunity cost as a factor for 'costs' of the wall. That is assuming you can find a valid way of measuring it, it's hard to place an opportunity cost on a less-than-rational government budget since assuming money not spent on the wall would go to a cost effective alternative, rather then being wasted on some inefficient endeavor, is not always a safe assumption. Though I suppose claiming the interest on the national debt, on the argument the money used for the wall would otherwise not be spent and thus pay off (or not require borrowing against) the debt, would probably be a semi-valid minimum estimation of opportunity cost.

I'm looking for hard numbers from cited sources or valid statistical calculations for this question, some degree of rigor to prove the accuracy of claims. I am looking only at direct financial cost of building the wall, I'm not interested in any other claimed advantages/disadvantages of the wall, such as environmental impact, or whether the wall will lower crime from illegal immigrants, I've already asked a question about that latter claim.

I would like answers that can say whether the wall was cost effective before the government shutdown nonsense started. If for some reason you really wanted to address how the government shutdown changes the numbers you can, but I'd like to know what the anticipated ROI would have been even if government shutdown never occurred.

  • 20
    The fundamental problem with answering this question would be agreeing on the definition of what constitutes "Return on Investment" from the wall. While I agree it may be possibly to attribute X cost to Y program from illegal aliens, it is not, IMHO, possibly to fully equate $ value to the "return" part of the ROI in altering the flow of immigration. Too many externalities to apply to the value of a human life to properly calculate return here. There is a cultural shift that cant be priced accurately.
    – David S
    Dec 26, 2018 at 21:02
  • 5
    I don't see how this question can be close-voted as opinion-based when the OP is specifically asking for hard data on the matter.
    – Wes Sayeed
    Dec 26, 2018 at 23:35
  • 28
    As far as I'm aware, credible studies of illegal immigration conclude that illegal immigrants are a net benefit to the economy, not a net cost. So the only economic benefit of the wall would possibly be to improve the efficiency of Border Patrol operations on the southern border. But you also have to take into account the fact that there are be much more cost-effective ways to improve that efficiency.
    – phoog
    Dec 27, 2018 at 0:32
  • 9
    @phoog: Yes, I wonder who they think is going to be picking fruits & vegetables, or all the other hard and low-paid jobs that most Americans won't do, in the absence of immigrants. (And for the record, I have - working in a field, hearing someone shout "Migra!", and suddenly finding yourself all alone is a learning experience :-))
    – jamesqf
    Dec 27, 2018 at 5:41
  • 12
    There's another point that really ought to be addressed in any cost analysis of "The Wall". That is, will it actually reduce the numbers of illegal immigrants? As I think was mentioned, many are visa overstays. There's also a lot of sea coast out there, and as European experience shows, determined migrants can obtain boats.
    – jamesqf
    Dec 27, 2018 at 21:29

1 Answer 1


Best-case scenario? Fox News thinks the Wall will save lives by making it more difficult for cartels to bring drugs into the USA.

Middle-of-the-road scenario? Stanford put an actual monetary figure into play with its research: for every 19 cents we spend on this wall, it will give about 1 cent worth of benefit to low-income US workers. Oh, and it wouldn't slow the rate of drug smuggling.

Worst-case scenario? Trade war/embargo with Mexico, environmental ruination on a huge scale, and the loss of between 8 and 40 billion dollars that could have been used to repair crumbling infrastructure.

  • 3
    The Stanford study is pretty credible.
    – ohwilleke
    Jan 11, 2019 at 19:32
  • LOL. The Stanford study was based on highly questionable assumptions. Things like: the only people who benefit are workers. The numbers can be counted in tens of thousands. Yes, today we can use hindsight to laugh, but such studies have always been questionable. We make huge assumptions based on our biases. Real data: MILLIONS of people are now coming in annually. Many with nefarious intent, including terrorists. An effective wall system would be incredibly helpful. (Look at urban areas to see why. No enforcement==rampant crime. If nothing else, a wall lets CBP focus on tunnels etc ;)
    – MrPete
    Apr 24, 2023 at 20:28
  • @MrPete You wouldn't believe how often I laugh at peer-reviewed studies in well-established journals because the results don't mesh with figures my favorite media personality made up.
    – Carduus
    Apr 25, 2023 at 14:03
  • @Carduus perhaps more to the point: are you aware of just how AWFUL peer-reviewed studies are and have been? I recommend searching for the NOVA show, "What Makes Science True?" ... check the extensive bibliography. Visit metrics.stanford.edu -- there is an incredible crisis in modern science. The vast majority of the very best studies are later found to be largely or completely FALSE! Serious people are working out why, and how to correct our processes. Bottom line: it's incredibly hard to do science well.
    – MrPete
    Apr 27, 2023 at 3:59

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