Each mutual fund on this app can carry a rating, shown as a number out of a maximum (for example, "4 of 5"), together with a basis string that states plainly what the number measures. That basis is shown as real text everywhere the rating appears, deliberately — the rating exists to classify a fund's historical returns and volatility relative to similar funds, and is labelled that way explicitly rather than left to be read as anything more than that.

A rating like this is typically derived from a fund's returns over several past time periods, adjusted for the volatility (how much the fund's value has fluctuated) it took to achieve those returns, and compared against other funds in the same category — since a fund investing in, say, small companies is naturally more volatile than one investing in large, established ones, and comparing across dissimilar categories wouldn't be meaningful. A fund with a higher rating has historically shown a more favourable combination of return and volatility within its own category over the measured window; a fund with a lower rating has shown a less favourable one over that same window.

The rating is recalculated periodically as new return data becomes available, so a fund's rating can and does change over time as its more recent performance is incorporated and its oldest measured period rolls off. A fund with no rating shown is not the same as a poorly rated one — it means the fund hasn't been rated at all, commonly because it's too new to have enough historical data for the calculation, and this app displays "not rated" rather than treating an absent rating the same as a low one.

Because every part of the calculation looks backward — at return and volatility that has already happened — a rating is, by construction, a description of the past. It says nothing directly about a fund's underlying holdings today, its current expense structure, or what conditions the fund might face going forward, and none of those are captured by the number itself.