The Congressional Budget Office (CBO) and the Joint Committee on Taxation (JCT) still rely heavily on static scoring—a model that assumes changes to tax laws don’t influence economic behavior or affect GDP growth. It’s a method that may feel safer on paper but overlooks how real people and businesses respond to financial incentives. When it comes to shaping national policy, numbers carry the most weight. But in the federal budgeting world, especially on tax matters, the numbers we use don’t always tell the whole story. 

Limits of Static Scoring

Static scoring cuts tax rates. Then revenue is projected to fall by a proportional amount. It doesn’t factor in how individuals might work more or invest differently when their after-tax returns increase. While it may seem conservative, this model doesn’t hold up under real-world scrutiny.

Economists overwhelmingly agree. The incentives matter. Lowering taxes on income, investment, or business profits tends to spark more activity in those areas. People work more. Businesses hire and expand. Investment increases. This ripple effect can grow the economy and, ironically, even boost tax receipts over time.

This isn't just a theory; we've seen this play out across several pivotal moments in U.S. tax history.

Case 1: Kennedy’s Tax Cuts (1964)

In the early ’60s, top income tax rates hovered around a staggering 91%. President John F. Kennedy proposed a bold reduction, bringing the top rate down to 70%, on the belief that cutting taxes would energize the economy.

As Kennedy famously put it, “A rising tide lifts all boats.”

And it did. From 1961 to 1968, GDP averaged 5.2% growth annually. Unemployment dropped from 6.7% to 3.4%. Despite lower rates, tax revenues rose thanks to the booming economy.

Case 2: Reagan’s Tax Reforms (1981 & 1986)

President Ronald Reagan championed two rounds of sweeping tax changes. The Economic Recovery Tax Act of 1981 lowered top income tax rates from 70% to 50%, and the 1986 Tax Reform Act took them down again to 28%, while simplifying the tax code and broadening the base.

The results were substantial. Between 1982 and 1989, real GDP grew at a 3.5% annual rate. About 20 million new jobs were created. Federal tax revenue nearly doubled, rising from $517 billion in 1980 to $991 billion in 1990.

Yes, deficits climbed during this time, but much of that was tied to spending and defense costs, not a collapse in tax revenue as static models had forecasted.

Case 3: Trump’s Tax Cuts (2017 - TCJA)

The Tax Cuts and Jobs Act (TCJA), signed by President Trump in 2017, slashed the corporate tax rate from 35% to 21%, adjusted individual brackets, boosted the standard deduction, and expanded the child tax credit.

In the two years before COVID hit, GDP grew by 2.9% in 2018 and 2.3% in 2019. Wage growth picked up, especially for lower-income workers. Companies repatriated over $800 billion in overseas earnings in 2018 alone. Federal revenues, despite rate cuts, rose from $3.3 trillion in 2017 to $3.5 trillion in 2019.

The CBO had projected a $1.5 trillion shortfall from the tax changes. But real-world dynamics—like job growth, investment, and rising incomes—helped offset that hit. Static scoring missed these vital shifts.

Static vs. Dynamic: A Skewed Policy Lens

What’s common across these tax reform periods? Static scoring consistently underestimated the economic rebound triggered by smarter, growth-focused tax changes.

While the CBO sometimes provides dynamic analysis in supplemental material, it doesn’t fold that insight into the official budget numbers. As a result, Congress is often working off an incomplete picture—one that ignores critical factors like:

• Growing labor participation
• Rising private investment
• Consumption driven by higher disposable incomes
• An expanding tax base

This kind of blind spot discourages reforms that could enhance U.S. competitiveness and productivity.

Why Dynamic Scoring Matters

Dynamic scoring accounts for how people and markets react to policy changes. It’s not about rosy predictions it’s about realism. By modeling effects on GDP, jobs, wages, investment, and eventually tax receipts, dynamic scoring offers a fuller, more grounded forecast.

Critics argue it’s too uncertain or politically influenced. But rather than avoiding it, we should demand transparency and scenario-based projections not cling to a model that ignores actual behavior.

Conclusion: Time to Modernize the Scoreboard

CBO’s continued use of static scoring doesn’t just misrepresent fiscal impacts it actively warps the debate around tax policy. It paints a false picture, discouraging reforms that could strengthen the economy over the long haul.  CBO was established in 1974, to provide Congress information on analysis related to fiscal matters.  

To build a smarter, more growth-oriented budget process, Congress should:

• Mandate dynamic scoring for all significant tax proposals
• Publish outcome ranges based on varying economic responses
• Incorporate lessons from past reforms into fiscal planning

Only then can policymakers craft legislation that reflects how economies truly work and set the stage for a future built on innovation, investment, and broad-based prosperity.