Not true. Market isn't random at any timeframe.
Otherwise, how would trading work at all?
I've noticed: the longer time frame the more trends > noise. At intraday level: trends = noise. Trading can work well with longer time frames.
In this kind of trading timeframe, however, it's more important to watch time & sales and market depth to get an idea what's going on, rather than just look at charts which is why you probably think it's "random".
As far as I know trading systems don't use market depth, just prices. I don't know how can you code such a system. Such scalping method can be rather based on intuition, feeling. Time & sales is also the price action. Metooxx wrote that he uses scalping systems.
I tend to say "When the charts lie, watch the order flow".
What I really mean by that is that sometimes the depth/TS will tell you what's gonna happen before the charts do.
Well, often I can state the opposite. Sometimes order flow lies. When I watch bid & offer sizes in relation to price action I frequently see fake signals.
The "edge" you're asking for - let me try to summarize a few:
-Larger cumulative profits
-Higher trade frequency / consistency = no losing days
-Smaller drawdowns / smoother equity curve
Do you base these conclusions on hypothetical backtesting or on your actual scalping performance? Do you really have "no losing days"? BS alert flashes in my head right there! Metooxx, nitro, candletrader: do you have no losing days in scalping? Huh, let's trade on 8-tick chart, maybe we will have no losing HOURS

But first of all, it isn't the edge I was asking for. I've asked about the source of an edge. In your opinion (or experience?) edge lies in using patterns in market depth.
The most important factor which makes profitable scalping close to impossible are execution issues, IMO. You can use market or limit orders. With limit you can get better price but no guarantee of execution, as a result market can move against your position quickly, and you can try to "catch" it with limit orders for a long time without success. With market orders spread is your cost. And it's pretty high cost. Say you make 30 trades per day on ES. Spread is 0.25 pts x 30 = 7.5 pts ~ half of intraday range.