What do you get when you combine a measure of fear vs complacency, a measure of low vs high valuations, and a measure of low vs high levels of bullishness? In this particular ChartBrief you get the "Euphoriameter". The working assumption is you have a euphoric market when people are complacent, valuations are high, and bullishness is rife. Thus the higher this indicator is the more likely it is that the market has entered into a euphoric mania, particularly if it signals during a mature bull market.
This is your fairly typical contrarian sentiment indicator, clearly from history we can tell the signals are more powerful on the euphoria side during a mature bull market (from a bearish contrarian perspective). Likewise contrarian bullish signals are most powerful when the indicator reaches a low after the market has undergone taken a major correction or bear market. At the moment the indicator has gone from Euphoric back down to fairly neutral or depressed levels following the mini-bear-market of 2015/16. This will be an indicator to watch as the market heads higher...