How We Detect GE Dumps Before They Happen
Every OSRS flipper has been there. You check the Grand Exchange, buy an item at what looks like a fair price, and watch it crash 30% over the next hour. By the time you realize what happened, you're holding a bag.
Grand Flip Out detects these dumps in real time. Not after they've happened. Not with a 5-minute delay. In real time, scored from 0 to 100 based on severity, with recovery timeline estimates.
Here's how the math works.
The Problem: GE Prices Don't Crash Randomly
A dump isn't just "the price went down." Prices fluctuate constantly. What makes a dump different is sustained negative drift — the price keeps falling, doesn't bounce back, and volume patterns shift in a specific way.
Regular price noise looks random. A dump has structure:
- Day 0: Sudden price drop, 20-80% below recent average
- Days 1-3: Continued selling pressure, spread widens dramatically
- Days 4-14: Supply dries up, early buyers enter, spread starts tightening
- Weeks 2-6: Organic recovery (if the item has structural demand)
The question is: how do you detect the dump at Day 0, not Day 7?
Layer 1: CUSUM (Cumulative Sum Control)
CUSUM is a statistical process control technique from manufacturing quality assurance. It detects when a process shifts away from its expected mean — exactly what happens during a dump.
For each item, we maintain two CUSUM statistics:
S_high— detects upward regime shifts (pumps)S_low— detects downward regime shifts (dumps)
When S_low exceeds our threshold, we flag the item as "dumping." The threshold is adaptive — volatile items need a higher threshold to avoid false alarms, while stable items trigger on smaller deviations.
CUSUM catches dumps that simple percentage-change alerts miss, because it accounts for the sustained nature of the drift. A 5% drop that bounces back won't trigger CUSUM. A 3% drop that continues for 6 consecutive polls will.
Layer 2: Z-Score Anomaly Detection
Every 5 minutes, we compute the z-score for each item — how many standard deviations the current price is from its recent mean. This gives us a universal "how unusual is this?" metric across all 4,400+ items.
- |z| < 2: Normal fluctuation
- |z| 2-3: Warning — unusual movement
- |z| 3-5: Alert — significant deviation
- |z| > 5: Critical — extreme event (dump or pump)
Z-score alone isn't enough (items can naturally be volatile), but combined with CUSUM regime detection, it tells us both that something unusual is happening AND how severe it is.
Layer 3: VPIN (Volume-Synchronized Probability of Informed Trading)
VPIN measures order flow toxicity. In the OSRS context, it estimates whether the current trading activity is driven by informed traders (who know something you don't) or uninformed traders (regular flippers).
High VPIN on an item means someone is aggressively selling with information — maybe they know about an upcoming nerf, or they're dumping a position ahead of bad news. GFO tracks VPIN across 1,966 items and flags 20+ elevated items at any given time.
Layer 4: Dump Scoring (0-100)
When multiple layers agree, we compute a composite dump score:
- Price drop magnitude: How far has it fallen from the baseline?
- Volume pattern: Is volume spiking (panic selling) or drying up?
- CUSUM regime: Is this a confirmed regime shift or just noise?
- Historical context: Has this item dumped before? How long did recovery take?
- Item class: Is this a consumable (high recovery probability) or cosmetic (may never recover)?
- Time of day: Dumps during UK peak hours (14:00-22:00 UTC) behave differently than off-hours
Scores above 65 are "confirmed dumps." Scores 40-65 are "likely dumps." Below 40 is "watch but don't act."
Layer 5: Recovery Prediction
Detecting the dump is only half the value. The real question is: should you buy it?
We use an Ornstein-Uhlenbeck mean-reversion model to estimate recovery probability and timeline. This is the same model used in quantitative finance to price mean-reverting assets.
The key parameter is theta (θ) — the speed of mean reversion. Higher theta means faster recovery. We estimate theta from recent price history and combine it with volume data to predict:
- Half-life of recovery (how long until 50% price restoration)
- Whether recovery is likely at all (some dumps are permanent — nerfs, content removal)
- Estimated exit price and timing
Layer 6: Neural Network Confidence
Grand Flip Out is the only OSRS tool with a neural network. Our living-nn system trains 24/7 on GE data, learning patterns that statistical methods can't capture.
The NN doesn't replace the statistical layers — it provides a confidence modifier. When the NN agrees with the dump score, confidence goes up. When it disagrees, we flag uncertainty. This multi-layered approach means we catch dumps that any single method would miss.
Layer 7: Recipe Ripple Chains
This is unique to GFO. When one item dumps, related items often follow — but with a delay.
Example: Nature rune crashes 20%. Within 1-3 hours, alchable items see a demand surge (alchemy becomes more profitable). If you detect the nature rune dump at Hour 0, you can position in alchables before Hour 1.
We track 16+ production chains (ore→bar→item→alch, herb→potion→consumption, etc.) and predict cascade effects in real time.
What This Means for You
When GFO detects a dump, you get:
- The item name and current price
- Dump score (0-100) with severity classification
- Recovery probability and estimated timeline
- Related items that might be affected (ripple chain)
- Whether this looks like manipulation or organic movement
All of this is free. No paywall. No premium tier for dump alerts. The intelligence is the product.
The Competition
Other tools show you that a price dropped. We show you why it dropped, whether it will recover, and when to buy. That's the difference between information and intelligence.
07Flip uses basic percentage-change alerts. GE Tracker shows historical charts. Neither uses CUSUM, VPIN, mean-reversion modeling, neural networks, or ripple chain analysis. We use all of them, simultaneously, on every item in the GE.
Try it at grandflipout.com. It's free.