I have noticed that in terms of US Dollars both BTC and alt coins have a positive correlation.
![](https://ip.bitcointalk.org/?u=https%3A%2F%2Fi.imgur.com%2FkX2Tqm6.png&t=665&c=mkJtzZ8kgmdVbg)
Yes, highly correlated = 0.841...
Above is a carefully constructed semi-cap weighted Alt Index (blue) vs BTC (gold)...
That had about 12 alts summer 2013... and now 22 alts summer 2014.
A coin is not added to the above index unless it's been on an exchange for 4-8 weeks...
So you are missing all the early mining gains and listing pumps...
Even without the real action experts capture... Alts as a universe have kept up with BTC gains.
There is a concept "fooled by randomness"...
Where most people own a few alts and use the "eye test"...
Then develop this "feeling" that BTC/Alts are negatively correlated... but it's mostly lags.