Best example is the last fast drop down to $319.9 yesterday on Bitstamp WHICH WAS IGNORED by all other exchanges. No other exchange dropped as fast and as much as Bitstamp did. Therefore Bitstamp is clearly not leading anymore and it makes no sense to forecast 15 minute trends based on an exchange which is not leading. It's a waste of time if you ask me unless you start analzying the Chinese exchanges.
I would especially recommend to analyze an price average of the three leading Chinese exchanges which get by typing this into Tradingview as symbol:
Also BTCChina didn't have margin trading for a long-time so other exchanges are more popular and hence the data on BTC China is more reliable. I even think that Chinese traders look more at BTCChina for the long-term trend as we do look at Bitstamp. Because before the last rally in early November both Huobi and OKCoin had already a new pivot low and started a rally from there, while BTCChina had not. And only when BTCChina had the new pivot low 2 days later the entire rally really started. Therefore I think BTCChina is leading long-term overall even more than Huobi/OKCoin.
So if you would analyze BTCChina you would get two benefits over Bitstamp: Traders look for new trends at China not Bitstamp. Oldest but still competitive exchange there is BTCChina. Most manipulation is going on at Huobi and OKCoin. BTCChina is lagging but confirming the overall price trends at Huobi and OKCoin. Therefore with BTCChina you would get more reliable BTC trends faster than Bitstamp. At least I switched to looking at BTCChina prices and 90% of the time I got much more reliable trends than looking at Bitstamp.