Tick Data vs Minute Data: The Gap, Measured

Everyone repeats that tick data is more accurate. Almost nobody quantifies how much, which makes the advice useless — you cannot decide whether to pay for something whose benefit is undefined. So here is the measurement, run across 1,911,141 EURUSD one-minute bars. The answer turns out to depend almost entirely on how tight your stop is, and the relationship is far steeper than most traders expect.

The ambiguous bar problem

Here is the specific thing lower-resolution data cannot tell you.

You enter at the open of an hourly bar with a take-profit 10 pips above and a stop 10 pips below. When the hour closes, the bar's high reached 12 pips above your entry and its low reached 11 pips below. Both levels were touched. Did you win or lose?

The hourly bar cannot say. It records four numbers — open, high, low, close — and discards the order in which the high and low occurred. The trade is genuinely undetermined at that resolution, and every backtesting engine has to guess. Most guess pessimistically (assume the stop), some guess optimistically (assume the target), and a few flag it. Whatever the engine chooses, that trade's result is an assumption rather than a measurement.

Higher-resolution data resolves it, because the minute bars inside that hour show which level was reached first. So the practical question becomes: how often does this actually happen?

The study

Method. Take 1,911,141 EURUSD one-minute bars spanning 3 January 2021 to 30 April 2026 and aggregate them into 31,852 hourly bars. At each hourly open, place a symmetric bracket — equal take-profit and stop-loss distance. Count the hourly bars where both levels fall inside the bar's high-low range, meaning the hourly bar alone cannot resolve the outcome. Then use the underlying minute path to determine which was actually hit first.

Run at four bracket sizes, on 17 August 2026:

What the numbers actually say

The effect is non-linear, and steeply so

Halving the bracket from 10 pips to 5 does not double the ambiguity — it multiplies it by more than five, from 3.01% to 16.45%. Going from 20 pips to 5 multiplies it roughly seventy-fold. Resolution risk does not scale with your stop distance; it explodes as the stop tightens.

At a 5-pip bracket, one trade in six is a coin flip

This is the headline. If you backtest a 5-pip scalping strategy on hourly bars, 16.45% of your trades have outcomes your data cannot determine, and the true answer is close to random. A strategy showing a 55% win rate in that test could plausibly be at 47% — the margin of the uncertainty is wider than most edges being claimed.

At a 40-pip stop, resolution is irrelevant

Three ambiguous bars in five years. If you are swing trading with wide stops, paying for tick data buys you almost nothing on this axis, and you should spend the money on more history instead. This is the finding most likely to save a reader money, so it is worth stating plainly: the standard advice to buy the highest resolution available is wrong for a large share of traders.

What this study does not prove

Being precise about scope, because it would be easy to overclaim here.

• This measured minute data resolving hourly ambiguity, not tick data resolving minute ambiguity. The mechanism is identical one level down — minute bars discard the intra-minute path exactly as hourly bars discard the intra-hour path — but the specific percentages for tick-versus-minute would need tick data to compute, and are not claimed here.
• It does not address spread, which is a separate and often larger problem. Mid-price data of any resolution makes execution cost invisible. A 5-pip target against a 1.5-pip spread loses a third of its edge to costs that no amount of resolution reveals.
• It is one instrument over one five-year window. EURUSD from 2021 to 2026. More volatile pairs would show higher ambiguity at the same bracket.
• Symmetric brackets only. Asymmetric risk-reward setups would produce a different, generally lower ambiguity rate.

You can reproduce it. The inputs are the public one-minute archive and the method described above.

What to do with this

For the bottom two rows — which is most discretionary swing and intraday trading — one-minute data across several years is the right tool, and it is free. FXAbsolute gives 28,412,683 one-minute bars across 15 instruments spanning 2021 to 2026, with no account and no download.

For the top row, be honest that you need more than we offer: our data is mid-price OHLC with no spread modelling, which makes it the wrong tool for a 5-pip strategy regardless of resolution. BacktestFX offers free tick data with real spreads, and Forex Tester's Super Data tier offers tick data with floating spread. Use those instead — a scalping backtest on our data would tell you something confident and wrong.

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