And yet even another projection

I don't claim to be able to project the future. But there might be a grain of truth here somewhere. So here is my latest.

Assumptions:
1. A crisis point will be reached when debt held by the public, less debt held by the Federal Reserve, ("net public debt") exceeds 100% of GDP.
2. GDP figures are taken from CBO projections through 2021 (when the number is 23830) and then it will grow by 4% thereafter.
3. The debt held by the public will grow at 9%/year, starting at 10127 in 2011.
4. The debt held by the Fed grows at 5%/year, starting at 1569 in 2011.

Using these assumptions, the crisis point will be reached in 2024 when GDP will be 26806, and net public debt is 28089.

Update:  This is model J-1.  Model J is the theory that debt held by the public, less debt held by the Federal Reserve, cannot exceed 100% of GDP.

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Update (10/28/12): This is flawed, for two reasons.  A 9% growth rate in the debt may be too high, and it is too simplistic just to assume a given growth rate.  This should follow budget projections for at least 10 years.  Second, the 100% number isn't necessarily a threshold, and the number is probably higher, at least 125%.