What is Product Assortment Efficiency? (And Why Every Shopify Store Needs to Track It)

Product assortment efficiency. It’s one of those things nobody tells you to look at – until you’re buried in low-performing products and don’t even know why. Most Shopify stores never track this. But it’s one of the easiest ways to spot where your store’s collections are bloated, underperforming, or quietly draining your revenue.

What is Product Assortment Efficiency?

Let’s keep it simple – product assortment efficiency means how well your products sell compared to how many you offer. If you’re selling 50 products and only 3 of them are driving 90% of the revenue… that’s inefficient. You’re using space, ads, and energy for things that aren’t pulling their weight.

A high product-to-sales ratio = good. Low ratio = red flag.

Now zoom out. What about collections? Tags? Subcategories? How many different pieces are in those, and how many actually bring in cash? That’s where collection performance metrics come in – especially when powered by Shopify product analytics tools like Portfolytics.

Why Shopify’s Default Analytics Miss This Critical Metric

Shopify’s native analytics show you sales. Great. But they don’t show you how efficient your assortment is. They don’t say:

• “Hey, this collection has 40 SKUs but only 5 of them sold this month.”
• “This tag group has 100 products and barely moved €200 in sales.”
• “This main category has 3 subcategories. One’s carrying the whole thing.”

Shopify isn’t built to track SKU optimization or collection efficiency. Most apps aren’t either. That’s why tools that compare sales to the width of your inventory matter more than people think.

The Hidden Cost of Low Assortment Efficiency

Inefficient assortments kill stores slowly.

You get decision fatigue. Shoppers bounce because they’re overwhelmed by too many options. Ads underperform because you’re spreading clicks across too many underwhelming products. Merchants overstock. Money gets tied into the wrong things.

It doesn’t always show in your total revenue numbers – but your margins, conversion rates, and time spent managing inventory all suffer.

And worst of all – it makes scaling harder.

Real Example: Collection A (10 products, €50k) vs Collection B (50 products, €45k)

This is what happens when you don’t look at product assortment efficiency.

Collection A: 10 tightly picked items. €50,000 in sales last month.

Collection B: 50 products, many styles, wide range… €45,000 in sales.

At first glance? They’re close. But look again: Collection B is 5x the size but earns less. That means each product on average is far less efficient.

Here’s the thing – this isn’t rare. It’s happening in your store right now unless you’ve done an audit.

How to Spot Inefficient Collections in Your Store

So how do you actually find these weak spots? Start with:

Step 1: Product-to-sales ratio per collection

For each collection:

• How many products are inside?
• How much did it sell in a given time period?

Compare. You’ll often find bloated collections with underwhelming sales. Tags are even worse – they usually have 10+ products per tag.

Step 2: Main and subcategory efficiency

If you’re using Portfolytics, you can view:

• Sales per main category
• Sales per subcategory
• Number of unique products in each

Click once, and you’ll see which category structure is pulling its weight. If one main category sells €20k with 15 products and another sells €22k with 80 products, the former is doing better.

Step 3: Product-level drilldowns

Look at your worst-performing products inside each collection or category. If they haven’t sold in 90 days… ask why they’re there.

Why Product Assortment Efficiency Matters More Than Total Sales

Here’s the trap: you see €100k in total sales and think you’re fine. But you’re carrying 500 SKUs. That’s €200 per SKU. That number alone doesn’t tell the whole story – some products may be doing €5k each while others sell nothing.

This matters when:

• You’re planning paid ads
• You’re ordering stock
• You’re forecasting for peak season
• You’re expanding to new markets

Stores with high efficiency scale faster. They market better. They spend less. They feel easier to run.

Getting Started: Your First Efficiency Audit

You don’t need to overhaul everything at once. Start simple.

• Export your sales by product from Shopify (or use Portfolytics to skip the spreadsheets)
• Group them by collection or tag – literally one click in Portfolytics
• Count how many products sold more than 5 units last 30 days
• Count how many sold zero

If more than 30% of your products didn’t sell… your assortment is bloated.

From here, either:

• Trim down products
• Group better
• Highlight winning collections

With Portfolytics, this takes under a minute – click your category, subcategory, or tag, and you’ll see your product-to-sales ratio. No Excel. No guesswork. Just clarity.

In Closing

Most Shopify merchants chase traffic or new SKUs when they should start by making their current store tighter. Better assortments lead to better decisions, higher returns, and less chaos.

Don’t ignore product assortment efficiency – it’s one of the highest leverage metrics you can track today.