> FICA / Payroll Taxes
I run a business, from my perspective the meaningful number is the total payroll cost for the employee. Taxes are taken before it even leaves my pocket and goes to the employee, and then more and more taxes by the time the employee finally sees it. You can't waive away the taxes just because the law says you can't show the true tax burden on the pay stub.
> Opportunity Cost
There are real, direct, added costs to choosing to work. It's reasonable to subtract those from salary when trying to calculate the net benefit of working. Just like there's an opportunity cost for waiting in line for bread. It's a real thing.
> $115300 -> $78,900 vs. $0 -> $44,011 (for a gap of $35k)
First, you can't take home quite $78,900 on $115,300 -- you've shifted up income but haven't adjusted taxes accordingly. From my perspective that employee is earning more like $140,000 (you can't just waive away the cost of paying for all those benefits that otherwise would be provided free by the government, just because they are taken out of your earnings before you see them).
Second, you can't just count $100 / pay period as the cost of insurance. It's the full cost of the plan (up to almost $24k / year for Platinum insurance for a family of 4) that has to be paid every two weeks at payday. Benefits are tax advantaged income, income paid out before you see it, but income all the same. If you are self-employed all this becomes obvious, but if you've never worked outside a W-2 the true cost is very much hidden out-of-sight.
Employer group insurance plans are more expensive than individual plans, which are obviously way more expensive than free means-tested plans. Going from $0 -> $30k you lose about $8k of value from losing Medi-Cal and going to the Cost-Shared Silver Plan. Going from $30k -> $60k you lose another $12k of subsidies. "Total actuary value" of having Medi-Cal is around $20k / yr for a family of 4. So if you are at $0 income, it's not just +$12k for ACA subsidies, it's more like +$20k for Medi-Cal since it's comparable coverage to a Platinum plan.
Third, yes the EITC phases-in and phases-out, it doesn't mean it's not a cost you pay for earning more. It's a curve and it's not a straight line, but it's still a real refundable tax credit that is clawed back as earnings increase over $24k. I agree it's impossible to maximize all benefits concurrently, it's a very complex equation with local and global minima/maxima. One day I really hope to be able to program it and put in on GitHub.
> Making financial progress on $100k income is challenging
So very true! Even per all your numbers, which are way more conservative than mine... the 'net benefit' to the family of earning "$115,300" of income (~$140k payroll) is only $35,000 !! (the gap)
And if you dig deep into all the assistance available, start counting things like income-based rent control, income-based property tax limits, income-based car registration fees, income-based electricity bills, etc.... you can easily erode that $35k down to more like $15k.
Isn't that just astounding?! Starting at $140k of employee payroll expense, by the end of the year you've only added $15k of net cash benefit to the family?!
As they say, "What the actual fuck!"