The Stockopedia GM Rank is an equally weighted combination of Stockopedia's:
1) Growth Rank
2) Momentum Rank
We calculate these ranks for every company in the market, sum them and then re-rank the output from 0 (worst) to 100 (best). The stock showing the highest GM Rank will have the highest score across both contributing ranks.
We discuss the StockRanks in depth here here.