How We Score and Rank Products
By Zoltan Lukacsi. Last updated .
Every product on SmartValueLabgets a Value Score from 0 to 100, calculated by one of three formulas depending on its category, and recalculated whenever its Amazon price updates. We don't test products in a lab. The score is built from data anyone can check: Amazon prices, manufacturer specifications, published benchmarks and Amazon buyer ratings. This page lists the exact weights so you can see why one product ranks above another.
Where does the data come from?
Every number on the site comes from one of four sources:
| Data | Source | How often |
|---|---|---|
| Prices | Amazon US, read through the Keepa price-history API | Hourly batches that cycle through the whole catalog, so most prices are under two days old |
| Specifications | Manufacturer spec sheets and product listings (capacity, rated speeds, TBW endurance, warranty, ports) | When a product is added, and when we find a correction |
| Benchmarks | Published results: 3DMark Time Spy for graphics cards, Cinebench R23 for processors | When a product is added |
| Buyer ratings | Amazon star rating and number of ratings | Refreshed regularly through Keepa |
Each price shows how old it is ("today", "2d ago") beside it. Prices change often, so the price at Amazon checkout is the one that counts. Each category has a sanity range for prices, and a reading far outside it, such as a third-party listing at ten times the usual price, is ignored, and the product keeps its last good price instead of jumping in the rankings. Each new price is also compared with the product's own recent prices. A reading more than three times higher, or less than a third, is skipped unless Keepa's 30-day average for that listing confirms the new level, so a real price change still gets through within days.
How is the Value Score calculated?
The Value Score compares each product only with others in the same category: every input is scaled from 0 to 100 against the best and worst product in that category, then the weighted inputs are added up. A score of 85 means "better value than most products in this category", so an 85 NVMe SSD and an 85 router can't be compared with each other.
1. Storage formula
Used for drives and cards where capacity and speed can be measured on the same scale.
| Input | Weight | What it measures |
|---|---|---|
| Price per TB | 35% | Current price ÷ capacity in TB; lower is better |
| Read speed | 25% | Manufacturer-rated sequential read in MB/s |
| Endurance | 20% | Rated TBW per TB of capacity |
| Warranty | 10% | Manufacturer warranty length (table below) |
| Buyer rating | 10% | Amazon star rating, adjusted for how many ratings it has (explained below) |
Hard drives have no comparable speed or TBW rating, so they get fixed values for those inputs (15 for speed, 30 for endurance) and compete mainly on price per TB. Categories: SATA SSDs, NVMe SSDs, Hard Drives, External SSDs, NAS Drives, External HDDs, Memory Cards, USB Drives.
2. Benchmark formula
Used where one published number captures how much product you get: performance per dollar, meaning that number divided by the current price.
| Input | Weight |
|---|---|
| Performance per dollar | 65% |
| Warranty | 10% |
| Buyer rating (adjusted for number of ratings) | 25% |
| Category | Performance number used |
|---|---|
| GPUs | 3DMark Time Spy graphics score |
| CPUs | Cinebench R23 multi-thread score |
| Video Doorbells | Video resolution (vertical pixels, 1080p = 1080, 2K = 1440) |
| Smart Automation | Outlets × ecosystem support (Alexa + Google = 200 per outlet, + Apple Home = 300) |
| NVMe Enclosures | USB link speed (10Gbps = 1000, 20Gbps = 2000, 40Gbps = 4000) |
| Network Switches | Total port bandwidth in Mbps (8 × 1GbE = 8,000) |
| Portable Monitors | Refresh rate × resolution multiplier (1080p = 1, 1440p = 2, 4K = 4) |
| Surge Protectors | Surge rating in joules |
3. Buyer rating formula
Used for categories where no single spec captures quality, such as headphones, keyboards or monitor stands. Here, buyer satisfaction leads and price comes second.
| Input | Weight | What it measures |
|---|---|---|
| Adjusted buyer rating | 65% | Amazon star rating, adjusted for how many ratings it has |
| Price | 25% | Current price on a log scale; cheaper is better |
| Warranty | 10% | Manufacturer warranty length |
The same rating adjustment is used in all three formulas. It stops a small sample from beating a proven product. Each rating is blended with the category average as if it had 500 extra average ratings, so a 4.8-star product with 30 ratings stays close to the average, while a 4.6-star product with 50,000 ratings keeps its 4.6. The best-adjusted product in the category scores 100 on this input and the weakest 30. Categories: Monitors, RAM Kits, Motherboards, Power Supplies, CPU Coolers, PC Cases, Routers, Mesh WiFi Systems, NAS Systems, Webcams, Microphones, Streaming Gear, Smart Cameras, Smart Hubs, Gaming Monitors, Gaming Keyboards, Gaming Mice, Gaming Chairs, Gaming Headsets, Monitor Stands, Gaming Laptops, Video Editing Laptops, HDMI Cables, USB Hubs, Headphones & Earbuds, Everyday & Student Laptops.
Warranty points
| Warranty | Points |
|---|---|
| 5 years | 100 |
| 3 years | 60 |
| 2 years | 30 |
| 1 year | 10 |
| Unknown or other | 30 |
Every product page shows its own score breakdown, so you can see which input moved it up or down.
What the score leaves out
The Value Score measures value on paper. It can't judge things like how quiet a fan is, how a keyboard feels or how good an app is. Ratings partly reflect those, and the verdicts cover them where published sources do. A cheaper product often scores higher than a faster one, which is the point of a value ranking. If you need the fastest drive or the brightest screen, sort the category table by that spec instead.
How are verdicts and guides written?
Each product has a short written verdict saying who it suits, its main trade-off and which product to buy instead. Verdicts, guides and blog posts are drafted with the help of AI tools, then checked against the product's spec sheet, our catalog data and named sources, and edited and approved by Zoltan Lukacsi before publication. Our rules:
- We never claim hands-on testing, benchmarks or measurements we didn't run.
- Speeds, wattages and other specs name their source ("Samsung rates it at 7,450 MB/s").
- Verdicts don't quote prices, because prices change daily; the live price sits beside them.
- Amazon ratings are shown as Amazon ratings and are never presented as our own review score.
Which products do we list?
Every product is a live Amazon listing with a checked ASIN. We remove fake or relabelled listings, such as generic drives sold under "High Performance" names. A product with a missing or odd price stays listed, because the Amazon page always shows the real price, but it is left out of the score calculation until it has a valid price.
Does affiliate commission affect rankings?
No. We earn a commission when you buy through our Amazon links, at no extra cost to you, and Amazon sets commission rates by product type, not by brand. The formulas above are the only thing that sets the order, and no brand pays for placement. See our affiliate disclosure.
Found a mistake?
Specs and prices are checked, but errors happen. If a spec, price or verdict looks wrong, send us a messageand we'll correct it. Fixes to the formulas themselves are recorded on this page with a new update date.