Does the Vortex Indicator strategy beat buy & hold on Intuitive Surgical? (ISRG · backtested honestly)
The Vortex Indicator builds two lines from the distance between each bar and the prior bar's opposite extreme — VI+ from this high versus the prior low, VI− from this low versus the prior high — each divided by the true range summed over a lookback.
Over this period, Vortex Indicator on Intuitive Surgical returned +15.3%, while simply buying and holding returned +21.4% — it lagged buy & hold by 6.1 points, with a worst drawdown of -39.1%. It traded 61 times and sat in cash about 49% of the time. It's a mechanism you test — not a recommendation.
It lagged buy & hold over this window — that's a result, and a backtest you can kill for free just did its job. Re-tuning this same idea until it looks better only adds another shot at looking good by luck, so the honest next move is a fresh one: test a different strategy on Intuitive Surgical, or build your own — free. Most ideas die cheaply right here, and that's exactly how the rare one that holds up gets found.
Or stop here — walking away from an idea that didn't beat simply holding is a result, not a failure.
Run it yourself
Change the parameters and the window, then re-run — no account needed.
Have your own idea for Intuitive Surgical? Build and honestly test your own strategy — no code, costs on, measured against buy & hold.
Build your own on Intuitive Surgical →Two real trades from this backtest
Shown at the modeled fills — entries at the next open, protective stops and targets at their level; costs on. A single trade is never a signal and says nothing about the next one — not the best or worst, a middling winner and a middling loser among the completed trades.
61 trades total — 25 winners, 36 losers (41% won). Below is one of each, not a scoreboard. One position is still open at the window end — its result is unrealized and is counted in the totals above at its current mark, not shown as a card below.
- Entry. A long entry fired; filled at the next open on 2025-02-14 at $593.16 — never the signal bar's own close.
- Held. 7 daily bars.
- Exit. Exited on 2025-02-26 at $570.85 (the exit rule fired (filled at the next open)).
- Result. -3.86% after costs.
The worst single trade in this whole test reached -11.85%.
- Entry. A long entry fired; filled at the next open on 2025-04-11 at $489.27 — never the signal bar's own close.
- Held. 1 daily bars.
- Exit. Exited on 2025-04-14 at $502.27 (the exit rule fired (filled at the next open)).
- Result. +2.56% after costs.
Trading costs + slippage (0.10%) are already deducted from every figure above. One trade is never the edge — it's the whole distribution (the win rate, the losers, the reality-check) that matters; this just makes the mechanics concrete. It describes the past; it is not a prediction.
A live badge that re-runs itself and links back here. Free to embed on any blog, newsletter or forum — it shows the honest result, beat or lagged.
<iframe src="https://stratsemble.com/embed/intuitive-surgical-vortex-backtest" width="360" height="340" style="border:0;border-radius:12px;max-width:100%" loading="lazy" title="Does the Vortex Indicator strategy beat buy & hold on Intuitive Surgical?"></iframe>- • The strategy line is Vortex Indicator on Intuitive Surgical; the dashed line is simply buying and holding ISRG. Beating the dashed line is the whole point — many strategies don't.
- • Max drawdown is the worst peak-to-trough fall you'd have sat through. A higher return with a much deeper drawdown is not obviously better.
- • Every fill assumes next-open execution with costs & slippage on — no acting on prices you couldn't have known.
- • A small number of trades means a small sample. Treat a great-looking result on a handful of trades with suspicion.
This is a hypothetical backtest of a well-known mechanism on past data. It is not advice, not a prediction, and not a claim that the strategy works. I hold no funds and place no orders. The value here is the ability to test an idea honestly — see where it would have helped, and where it would have hurt — before you ever risk real money on your own broker.
How this is computed → · who's behind it · where a backtest fits
See what actually beats buy & hold — most don't, here are the rare few that do →