Hey there,
The growth score is based on 3 groupings - valuation, growth and risk. Each grouping contains a number of data points and companies are ranked accordingly. So a company with a high growth score is likely to have a history of consistent growth, strong expected growth rates, good valuation and lower-risk profile. Keep in mind, that this is strictly from a 'growth' mindset and is entirely data-derived. For example, there could be a reason why it is trading at cheap valuations, so we always recommend a deeper dive regardless of their score. We consider these lists as a starting point for further due diligence. Average analysts estimates are used for expected growth rates.
As for the comment around 10-yr predicted forward growth rate? No. The growth rates are based on expected growth over the next two years. To be honest, anything beyond that requires a significant amount of assumptions and rarely proves accurate. There are just too many factors that change over a 10-yr period to accurately predict a growth rate which is why you see very few estimates beyond 3yrs. That said, we do take into account the company's historical performance when it comes to growth. If a company has a strong growth history and has proven capable, it is may be more likely to hit expected growth rates. The vice versa can also be true.
Bottom line is the score can be used as a starting point for further due diligence. Worth nothing many of the best performing stocks on the TSX like CSU, TFII, GSY, EQB, BYD, WCN, etc - were all featured among the top ranked growth stocks for extended period of times over the past handful of years. THat said, never use the list in isolation, but it makes for a great starting point.
Mat