Is TradingView's Strategy Tester Lying to You? Bar Magnifier, 'On Every Tick', and Realistic Fills Explained

What the Tester Is Really Doing

Every strategy test in TradingView works from the same raw material: OHLCV bars—open, high, low, close, and volume for each period. The problem is that a single bar does not tell you the sequence in which those price levels were hit. Did the high come before the low, or the reverse? The tester has to guess. That guess is where the gap between simulated results and real trading begins.

By default, the tester assumes your strategy executes at the open of the next bar after a signal fires. That is one of the more honest assumptions available—you do not get to trade at a price that has already closed. But several other defaults are quietly generous: zero commission, zero slippage, and unlimited liquidity at whatever price the model selects. Those three omissions routinely account for most of the flattering performance you see before you start trading a strategy live.

The Three Calculation Modes

Close (default): Orders execute at bar close or the next bar's open, depending on your recalculate settings. Clean, fast, and relatively honest—if your strategy only looks at bar-close data and you allow a one-bar execution lag, this mode has low fill distortion. Most strategies tested on 1-Hour, 4-Hour, Daily, and Weekly charts work reasonably well here.

On Every Tick: This mode does not use real tick data. It constructs a simulated intrabar price path by interpolating between the open, high, low, and close of each bar. The interpolation follows a fixed sequence—typically open → high → low → close, or open → low → high → close depending on bar direction—which means the tester can fill a stop or limit order at a price the actual market may have only touched briefly, or never in a tradeable way. For strategies with tight stops or intrabar limit orders, 'On Every Tick' often looks better than reality without being more accurate.

Bar Magnifier: Instead of constructing an interpolated path, Bar Magnifier fetches actual lower-timeframe OHLCV candles to represent what happened inside your bar. The sub-bars are real historical data rather than a model. This substantially reduces the invented-path problem—your intrabar fills are anchored to something that actually traded. It is slower to compute and does not eliminate all fill uncertainty, since you are still working from candles rather than L2 order book data, but it is the most realistic option TradingView currently offers.

What Actually Distorts Results—and in What Order

Fill-mode choice gets most of the attention, but it is usually not the biggest source of inflated numbers. The most common culprit is missing costs. If you are running zero commission and zero slippage, your results are almost certainly too optimistic. A round-trip commission for a futures contract, a forex spread, or an ETF market order is not zero. Even a modest per-trade cost, multiplied across hundreds of trades, changes Sharpe ratios substantially.

The second source is look-ahead bias. If a Pine Script indicator uses the security() function without the correct lookahead parameter, it can quietly import future data into the signal calculation. The tester will not warn you, and the equity curve will look suspiciously smooth. Check any third-party script you did not write yourself before trusting its output.

Fill-mode distortion comes third. In Close mode, if your signal and execution happen on the same bar close, the tester gives you a fill that in live trading would be delayed by at least one tick. On Every Tick compounds this by simulating fills at prices that were theoretically crossed but may not have been tradeable. Bar Magnifier reduces this problem but does not eliminate it. A fourth, often overlooked source is position sizing: the tester assumes you fill at the modeled price regardless of order size or available liquidity, which overstates what large orders would actually achieve.

Does Bar Magnifier Fix the Problem?

Bar Magnifier is a meaningful improvement for strategies that rely on intrabar execution. But it will not rescue a strategy with missing commissions, a look-ahead bug, or unrealistic position sizing. Those problems sit upstream of fill mode and need to be addressed first.

For strategies that execute at bar close on 4-Hour or Daily timeframes with realistic costs already set, the difference between Close mode and Bar Magnifier is often modest. The larger the timeframe, the less the intrabar path matters relative to your target and stop distances. Bar Magnifier delivers the most value when intrabar volatility is large and your fills depend on precisely where price moved within the bar.

One practical consideration: Bar Magnifier adds significant computation time. On long history windows, a single test run can take several minutes. If you are comparing many indicator variations or parameter combinations, validate candidates in Close mode with conservative slippage first, then confirm the best ones with Bar Magnifier before drawing any conclusions.

What Honest Backtests Actually Look Like

All results referenced here are hypothetical backtests, not financial advice, and not a prediction of future performance. They reflect what would have happened historically under the tested parameters—nothing more.

Across 660,005 backtests on 903 assets—covering 1-Hour, 4-Hour, Daily, and Weekly timeframes—only 26% of indicator and asset combinations beat a simple buy-and-hold strategy after realistic costs. The median best Sharpe ratio across all assets was 0.62. Those are the numbers you get when costs are real and execution assumptions are conservative. They are not the numbers you see with TradingView's default settings.

That said, 571 of the 903 assets tested had at least one indicator that beat buy-and-hold after costs. Indicators can work. The question is which one, on which asset, and under which conditions—and the only honest way to answer that is to set realistic costs before you evaluate anything else. Fill mode is a refinement. Costs are the foundation. Get the foundation right first.