Many times before an "event", I watch the options action in the ETF's that could be the most affected. Amazingly, a lot of the option activity PRIOR to the election results was pointing towards a Trump victory. I posted these out on Simpler Stocks BEFORE the election.
The theory was that if Trump was victorious, the markets would go sharply down. Obviously, the opposite happened eventually, but that was the prevailing theory. So I looked for unusual put activity in the major indexes, and unusual call activity in groups like infrastructure and drugs that would benefit from a Trump victory.
The first way I looked for these was to use an overall option scan. This INCLUDED every optionable product including ETF's and Futures. As seen, the put
action in the SPDR S&P 500 ETF (SPY) was overwhelmingly obvious.
The actual SPY option page was just as impressive.
Once I saw this activity, I decided to look for other huge put activity. As seen, the put activity in the PowerShares QQQ Trust ETF (QQQ) was much higher as well.
The iShares Russell 2000 Index ETF (IWM) had MUCH HIGHER put activity than call activity.
Before ANY big event, such as the Unemployment Report, the Fed Meeting, and the ECB, always watch the activity in the options market. It can really help your decision-making process!