Is it a standard practice to count scratch trades as losses in calculation of the win ratio and the expectancy?
All scratch trades cost you money. Commission & fees to get into the trade, commission & fees to get out of the trade and other costs that many forget about.
Unless its Ninjatrader stats, then a scratch is a win It may be better to just look at commission costs as a percentage of profits in some cases? I feel that as long as my total commission cost is under 5%, I'm happy. It used to be higher of course but I have the famous 10k+ hours. It is simpler for me and less prone to cause "penny wise and pound foolish" thinking.
A loss is a loss and why I will have rules of so many bars lock in one tick or new target is one tick if at a loss. And whether you paying retail or have a seat, one tick adds up. Most don't realize the significance of commissions will eat 100-150% of small accounts. If to have $5,000 account, do 6 Index futures trades a day at $4 equals $24 a day times 240 trading days is $5700. So making one tick on breakeven trades will pay commissions and lunch.