What is your formula? This doesn't match what I'm used to. For example, TLT has an inverse correlation with the US stock market (-0.32 according to PortfolioVisualizer.com), so I would expect it to be inversely correlated with QQQ.
Yes - some periods TLT does have negative correlation to QQQ. I was pretty surprised when I saw this since Bernstein did not see this in his analysis.
As I said it had been 15 years since I have been actively managed my investments. When the stock market dropped I was surprised that our investments hadn't actually dropped so I wanted to find out why. So I put together a google sheet and tried to replicate the Intelligent Asset Allocator with just ETFs. This only goes back to 2005.
First I put in all of the ETFs with weekly data going back to 2005 from GoogleFinance. I then added in the dividend yields - which most online analysis does not do. Then I just used the google sheets correlation function. I set up the sheet so I could slice and dice across different time periods. And then I chose my own asset allocation based on what I saw.
I also looked at the optimal rebalancing period. It looks like it is 2 years for this set of data.