Refining a factor instead of buying it: why the standard small-cap index is the wrong vehicle, and how to stack three screens into one.
1. Separate the factor from the vehicle — a right idea can have a contaminated index
The repeatable method
- Establish the factor with long-run evidence: how much it has paid, over how long, and in what units.
- Identify the default vehicle everyone uses to express it, and ask what that index actually admits.
- Name the contamination specifically — here, the proportion of loss-making companies in a broad small-cap index.
- Look for an index that filters the contaminant out before you accept a higher fee for it.
Here: "The smallest companies outperformed large caps by 1.8% per year on average" — then, "If you want to keep it easy, you could just buy the Russell 2000. But there is a problem with this index. It includes a lot of unprofitable companies."
Watch for
- Screening away the very stocks that produced the historical premium — much of the small-cap return has historically come from names that looked fragile at the time.
2. Stack screens in order of what they remove, and name the result
The repeatable method
- Start from the universe and apply a binary survival filter first — profitable for several consecutive years removes the tail without a judgement call.
- Then apply the ranking filters: cash retained per dollar of revenue, and cash generated per dollar invested.
- Cut to a fixed number of positions so the process is mechanical and repeatable.
- Give the combination a name you can hold yourself to — "Small-High Quality" — so the strategy can be judged rather than drifted from.
Here: SCOW's three stages — 600 small US companies, "only… the ones that have been profitable 7 years in a row," ranked on cash conversion and return on capital, "finally, the ETF buys the 80 best companies."
Watch for
- Every screen being backward-looking — seven years of past profits selects for businesses at the top of their cycle as readily as for durable ones.
3. Anchor a relative-valuation claim to its own long history, including when it ran the other way
The repeatable method
- Express the valuation as a ratio between two groups, not as an absolute multiple.
- Chart it over a long window and state where today sits within that range.
- Say explicitly when the ratio was inverted — a group that used to trade at a premium and now trades at a discount is a stronger claim than one that has always been cheap.
- Note the direction of travel: a gap that has kept widening is not yet mean-reverting, and the trade may be early.
Here: "Mid Caps: 29% cheaper than large caps. Small Caps: 32% cheaper… Between 2004 and 2020, smaller companies traded at a premium. Today, smaller companies trade at the lowest relative valuation in 25 years. Since 2020, the valuation gap has only become wider."
Watch for
- Composition change behind the ratio — large-cap index earnings are far more technology-weighted than in 2004, so the two groups are not the same objects being compared over time.
4. Rank the five uses of free cash flow, and screen for the one you want
The repeatable method
- List what a company can do with surplus cash: repay debt, reinvest, acquire, pay dividends, buy back stock.
- Decide which you are paying for and screen for it — reinvestment at high returns compounds inside the business and is not taxed on the way through.
- Use return on invested capital as the test of whether reinvestment is creating value rather than merely consuming cash.
- Be consistent about it, or say when you are not: elsewhere the same archive counts dividends and buybacks as return.
Here: "The most attractive option? Option number 2. You want companies to reinvest heavily in their own future growth." Against which: Visa's "3.1% per year" shareholder yield on
1 February, and Adobe's buyback cited as a reason to buy on
3 February.
Watch for
- Reinvestment with nowhere good to go — high ROIC on today's capital says nothing about the return on the next dollar.
5. Read a screened fund's top holdings before accepting its label
The repeatable method
- Pull the top ten and the sector split before buying any rules-based fund.
- Check concentration: what share of the fund the top ten represent, and whether any single name is oversized.
- Ask whether the businesses that came out of the screen match the story the screen tells — a "quality cash-generator" filter can surface cyclicals at peak cash flow.
- Weigh the fee against how much of the effect you could get from a cheaper vehicle.
Here: SCOW — "Information Technology (25.75%) and Financials (23.97%) make up almost half of the portfolio," the top ten are 39.44%, and the list runs Jackson Financial (6.29%), InterDigital, MarketAxess, Enova, Etsy, Enphase, Magnolia Oil & Gas, Bread Financial, Box, NMI Holdings — at a 0.59% expense ratio.
Watch for
- Consumer lenders and commodity producers dominating a "quality free cash flow" screen — their cash flow is real and their cycle is not in the rear-view mirror.
6. Run paired portfolios when your audience cannot buy the same funds
The repeatable method
- Accept the access constraint as a structural fact and build two books that express the same factors through locally-available vehicles.
- Make every transaction a matched pair, same size, same week, so the two books stay comparable.
- Report both CAGRs side by side and resist explaining a divergence you cannot attribute.
- Track which pairs diverge most — that is where the vehicles are not actually equivalent.
Here: "If you live in the US, you can't buy non-US ETFs. And if you live outside the US, you can't buy US ETFs." American book $10,346.84 at a 14.1% CAGR; non-American $10,976.71 at 18.5% — "Over time, I expect both portfolios to generate similar returns." The widest pair divergence: USMV +5.88% against MVOL.L +19.91% / +20.51%.
Watch for
- Currency doing the work — the non-American book buys in euros and is marked in dollars, so part of the 4.4pp CAGR gap is FX, not selection.
7. Check that the transaction matches the argument
The repeatable method
- After writing the case, state what you actually bought and reconcile it against the case.
- If you are not buying the vehicle you just argued for, give the reason and check that it covers every book you run.
- Keep the ticket size and cadence fixed so the argument cannot inflate the position.
Here: the issue argues that a plain small-cap index is contaminated by unprofitable companies, then buys plain small-cap indices — VB for $500 and IUSN.DE for €500. The stated reason for skipping SCOW is that it is "only available for investors in North America," which explains the European book but not the American one.
Watch for
- The spotlight becoming marketing rather than allocation — an ETF of the Month that is never bought is a recommendation with no skin in it.
Methods distilled from the archived Compounding Quality post for personal study. Not investment advice.