Choosing a stock scanner is mostly an exercise in detecting what isn't said. Every product claims to "beat the market" or "outperform" or "deliver signals." Almost none publish the data that would let you verify those claims. The asymmetry is the whole story: the products with real records publish them prominently; the products without real records hide behind proprietary algorithms and selected case studies.

This post is the buyer's checklist — five tests we'd put any scanner through, with the questions to ask and what each answer tells you. Tapeline is one of the products you might evaluate with these criteria; we score ourselves at the end so you can compare us against the same yardstick we'd apply to a competitor.

Test 1: Can you see every pick, including the losers?

This is the single most important test and the one most products fail. "Picks of the day" or "today's recommendations" are easy to publish; what's hard is publishing every pick that was wrong, with the same prominence, on the same page, with the original score and signal still attached.

The right answer looks like: "Yes, every top-10 daily pick we've ever published is logged at this URL, sorted by date, with the next-day return and the original score visible. The page is append-only — we can't go back and edit it. You can see every win and every miss."

Updated 14 September 2026: we used to hold Tapeline's own scorecard up as that answer, and it is not quite it. Our entries are not re-ranked or deleted, but we have corrected recorded values twice, and said so: prices on 25 August 2026, and scores from 18 May to 12 June capped on 15 June 2026. The answer to look for is a record whose corrections are dated and explained, not one that claims it can never change. (This post's summary said the same until today.)

The wrong answer looks like: "Our algorithm has a 67% win rate based on internal testing" with no link to the raw record. That's a marketing claim, not a verifiable statement.

Test it: ask for the URL of the daily picks log. If they hesitate, you have your answer.

Test 2: Is the benchmark named?

"Outperforms the market" is a meaningless claim without a named benchmark. Outperforms which market? The S&P 500? Russell 2000? Equal-weighted universe? Sector ETF? The choice of benchmark changes the answer by 5-10 percentage points annually.

Real answer: "Picks are back-checked against SPY (S&P 500 ETF) on a same-day, next-trading-day basis. Alpha is the pick's 1-day return minus SPY's same-day return."

Vague answer: "Outperforms the broader market" with no specific index named.

Tapeline's choice: SPY same-day-pick to next-trading-day-close vs SPY same window. Documented at /scorecard.

Test 3: Is the scoring methodology published?

This is the test most products fail through omission rather than misdirection. They simply don't disclose the formula at all. "Proprietary algorithm developed over X years" is the standard formulation.

The right answer names the inputs and is honest about how they're weighted. Tapeline's example: six named factors — Trend, Relative Strength, Fundamentals, Smart Money, Macro, and Momentum — weighted most toward Trend and Relative Strength and least toward Momentum, blended into a 0-100 composite, with each factor's contribution shown on every ticker. The factors and data sources are documented at /how-it-works.

What this enables: if the product underperforms in a particular regime, you can look at the score breakdown and see which factor is dragging. You can disagree with the weights and reason about that disagreement. With a black box, you can't do any of that — you can only stop using it.

Test 4: How fresh is the data?

"Real-time" means different things at different price tiers. On a free tier, "real-time" often means 15-minute delayed, because that's the IEX exchange delay limit on free consolidated feeds. On a paid tier, "real-time" usually means direct exchange data with sub-second latency.

Test it by checking the timestamp on a single quote. If it's behind the broker quote you'd see at your trading platform, you have your answer.

For composite scanners (like Tapeline), the question is slightly different: how often does the SCORE refresh, not just the underlying price? Tapeline's worker re-reads prices (delayed about 15 minutes) and recalculates the composite about every 60 seconds during market hours, but most of the score's inputs are daily readings, so a score usually changes about once a day. The public ticker pages show that score without an account, from a cached snapshot that can be an hour old or more. Updated 15 September 2026: this paragraph used to say the worker recomputed the composite "from fresh snapshot data" and that the public pages show a "live score"; on 14 September 2026 prices measured about 15 minutes delayed and ticker pages were cached snapshots.

Test 5: What's the unsubscribe / cancel friction?

This is the dirtiest test, but the most diagnostic. Products that are confident in their value make it trivial to leave. Products that depend on dark-pattern retention make it hard.

Check before you sign up:

Can you cancel from a settings page in one click, or do you need to email support and wait?
Is the trial auto-converting? Do you have to add a credit card?
What's the refund window?

Tapeline's policy: signing up is an email and a password, and the account it makes is a working one — the top ten scored rows. The trial is the part that takes a card, and it charges $0 until day 30; cancel from /app/billing in one click, 30-day refund window on monthly subscriptions. The published record — daily Top 10, scorecard, per-ticker pages, raw CSV/JSON — needs no account or card at all. We'd rather lose subscribers cleanly than retain them via friction.

How Tapeline scores against the checklist

Test	Tapeline
Public daily picks log with losers visible	Yes — /scorecard
Named benchmark	SPY, same-day-pick to next-trading-day-close
Public scoring methodology	Yes — six named factors at /how-it-works, contribution shown per ticker
Data freshness	Prices delayed about 15 minutes; composite recalculated about every 60 seconds in market hours, but usually changing about once a day; public ticker pages are cached snapshots, readable with no account (updated 15 September 2026; this cell used to say "60s composite refresh" and "live score")
Cancel friction	One-click cancel, 30-day refund. Signing up takes an email and a password; the trial is the part that takes a card, and charges $0 until day 30; the published record needs no account at all

What this checklist does NOT test

To be honest: none of these criteria tell you whether the product will work for YOUR specific trading style. You might need filter breadth Tapeline doesn't have. You might need international coverage we don't offer (US-only for now). You might prefer the analyst-rating focus Zacks does better than anyone. The checklist tells you whether the product is honest about what it does, not whether what it does matches your needs.

The two questions you need to answer separately:

Does this product publish enough evidence for me to verify their claims? (Checklist above.)
Does the thing they're publishing evidence FOR match what I actually want to do? (Read the product page + try the free tier + read the scorecard.)

Tapeline's pitch: we'd rather lose your business to a product that fits you better than win it via misleading claims. If the scorecard convinces you, the 30-day Premium trial is the way to see the rest — starting it takes a card, $0 is charged today, and one click cancels before the day-30 charge. If it doesn't, that's useful information too.

How to evaluate a stock scanner you can actually trust (5 criteria most fail).