How SaveIQ calculates price history

Where the prices come from

The price history of an Amazon.ca product comes from Keepa, a service that records Amazon prices over time. We read the last 90 days of it each time a product is checked.

For the products on our Price Watch list we also keep our own record. We read their prices daily and store each reading, which builds up to a twelve-month low and high that a check page shows next to the 90-day view.

The three numbers we compare

• The 90-day average. What the product has usually cost.
• The 90-day low. The best price in that period.
• The 90-day high. The worst price in that period.

Today's Amazon.ca price is placed against those three. Nothing else goes in: not the list price, not the size of a discount badge, and not what any store pays us.

The score

Each check gets a score from 0 to 100. It starts at 50, then:

• it moves 2.5 points for every 1% the price is below (up) or above (down) the 90-day average;
• it gains 15 points when the price is within 2% of the 90-day low;
• it gains 10 points when this is the lowest price in the history we hold;
• it loses 15 points when the price is within 2% of the 90-day high.

From score to call

• Buy: the score is 70 or more and the price is within 5% of the 90-day low. A price well under the average but far above a recent low is not a Buy.
• Wait: the score is 36 or less, or the price is 15% or more above the 90-day average.
• Fair price: everything in between. The product is at about its normal price.
• Not enough data: the last 90 days hold too little history to form a range, as with a product that has just launched. We say so instead of guessing.

One special case: if the price has not moved at all in 90 days, there is no dip to wait for. At that standing price the call is Fair; above it, Wait.

Confidence

Each call carries a confidence level, which depends only on how much history there is:

• High: at least 60 days of history, with 8 or more price changes in the period (or 40 or more over the product's life).
• Medium: at least 21 days, with 3 or more price changes (or 15 or more over its life).
• Low: anything less.

Is the discount real?

A check page also tests the discount itself, with three rules:

• List price above anything it sold for. The listing's list price is more than 2% above the highest price of the last 90 days. A percentage measured from it overstates the saving.
• List price at the peak. The list price matches the 90-day high but is more than 10% above what the product usually sells for.
• Raised, then dropped. The price reached a new high in the last 30 days, at least 10% above the high of the 60 days before and at least 20% above the usual price, and today's lower price only brings it back to about normal.

Amazon.ca does not always display the list price it holds for a product, so these notes describe the listing's data, not what the page necessarily shows you. We explain that in our study of 68 product pages.

Other Canadian stores

When we list another store, we have matched it to the same product, and a mismatch removes the row: another size or pack count, a refurbished or used item, another edition or platform, or a store page that does not name the model. A different colour is kept with a note. A store is only called cheaper when we have read its own product page, and eBay.ca listings must be new, from a Canadian seller, and not more than 25% under the Amazon.ca price.

These rules are strict on purpose, so many products show no other store. That means we could not confirm a match, not that nobody else sells it.

What is rule and what is AI

The call, the score, the confidence and the discount notes are fixed rules. No AI model decides them. AI is used for three things around them: understanding a search typed in plain words (in several languages), writing the short summary on a check page, and answering a question you ask about that product. Those answers are limited to the facts of the check.

What we cannot tell you

• What a price will be tomorrow or on a sale day. The call describes today's price against the past, nothing more.
• Prices older than our window. For a multi-year chart, Keepa and camelcamelcamel go further back; see how the three compare.
• The price in your cart. Amazon.ca prices change during the day and can differ by seller, so confirm the price there before you buy.

Independence

SaveIQ earns a commission on some purchases made through its links. The rules above have no input for commission, so a store that pays more cannot get a better call. See our editorial guidelines and affiliate disclosure.