Why is it so hard to decide how much a candidate's tax plan costs?


Over the next decade, Sen. Ted Cruz's tax plan could cost $8.6 trillion—or just $768 billion. Both estimates come from respected, non-partisan tax think tanks. So why are they wildly different?
Considering this question Friday at FiveThirtyEight, Ben Casselman notes that the Cruz estimates are perhaps an extreme disparity, but varying estimates are not uncommon:
[[{"type":"media","view_mode":"media_original","fid":"144219","attributes":{"alt":"","class":"media-image","height":"318","typeof":"foaf:Image","width":"597"}}]](FiveThirtyEight)
Subscribe to The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.

Sign up for The Week's Free Newsletters
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.
Most of the variety stems from "the broader economic impact of the various plans," he says, because "[c]hanges in tax policy have far-reaching ripple effects on the economy," which in turn affect revenues. That explains the difference between the static and dynamic estimates in the above chart — only the dynamic ones attempt to forecast how the candidates' plan will change the economy. That forecasting involves a greater degree of opinion and uncertainty than simply running the numbers for a static model, so economists' differing views can more significantly influence predictions.
Sign up for Today's Best Articles in your inbox
A free daily email with the biggest news stories of the day – and the best features from TheWeek.com
Bonnie Kristian was a deputy editor and acting editor-in-chief of TheWeek.com. She is a columnist at Christianity Today and author of Untrustworthy: The Knowledge Crisis Breaking Our Brains, Polluting Our Politics, and Corrupting Christian Community (forthcoming 2022) and A Flexible Faith: Rethinking What It Means to Follow Jesus Today (2018). Her writing has also appeared at Time Magazine, CNN, USA Today, Newsweek, the Los Angeles Times, and The American Conservative, among other outlets.
-
What does 'conquering' Gaza mean to Israel?
Today's Big Question Benjamin Netanyahu's cabinet has approved a plan to displace much of the Palestinian population while seizing and occupying the territory on a long-term basis.
-
Casey Means: the controversial 'wellness influencer' nominated for surgeon general
In the Spotlight Means has drawn controversy for her closeness to RFK Jr.
-
Trump taps Fox News' Pirro for DC attorney post
speed read The president has named Fox News host Jeanine Pirro to be the top federal prosecutor for Washington, replacing acting US Attorney Ed Martin
-
Warren Buffet announces surprise retirement
speed read At the annual meeting of Berkshire Hathaway, the billionaire investor named Vice Chairman Greg Abel his replacement
-
Trump calls Amazon's Bezos over tariff display
Speed Read The president was not happy with reports that Amazon would list the added cost from tariffs alongside product prices
-
Markets notch worst quarter in years as new tariffs loom
Speed Read The S&P 500 is on track for its worst month since 2022 as investors brace for Trump's tariffs
-
Tesla Cybertrucks recalled over dislodging panels
Speed Read Almost every Cybertruck in the US has been recalled over a stainless steel panel that could fall off
-
Crafting emporium Joann is going out of business
Speed Read The 82-year-old fabric and crafts store will be closing all 800 of its stores
-
Trump's China tariffs start after Canada, Mexico pauses
Speed Read The president paused his tariffs on America's closest neighbors after speaking to their leaders, but his import tax on Chinese goods has taken effect
-
Chinese AI chatbot's rise slams US tech stocks
Speed Read The sudden popularity of a new AI chatbot from Chinese startup DeepSeek has sent U.S. tech stocks tumbling
-
US port strike averted with tentative labor deal
Speed Read The strike could have shut down major ports from Texas to Maine