Ask HN: Why don't online retailers display inventory numbers? | Hacker News Reader

Ask HN: Why don't online retailers display inventory numbers?

3 pointsagentargoh12 comments

Is there a specific reason retailers don't include the inventory on an item when you are checking out?

I've had it happen so many times where I am thinking about buying something, let it sit in my cart for a couple hours, come back and it's sold out. If there was an inventory counter, I would've have bought it right away which is what I'm assuming is what the store would want.

Is there a reason that they don't do this?

Clearly they have the counts available on the items if they know when they are sold out. Is it a psychological thing or some kind of sales tactic? I don't get it.

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> Is there a specific reason retailers don't include the inventory on an item when you are checking out?

Some (e.g., Amazon) do indicate low-inventory warnings, including "Only n left".

> Clearly they have the counts available on the items if they know when they are sold out.

Inventory inaccuracies are not unheard of. Its quite conceivable that you don't know you've sold the last one that you will be able to deliver until you try to sell the next one, go to pick and deliver it, and find its not in deliverable condition (e.g., because it got damaged in the process of getting it ready for delivery), even with an otherwise-accurate inventory. Its also possible that you are expecting deliveries within the delivery window for a given order priority (or that you have a JIT ordering process and that your ordering time from your supplier has a turnaround within the delivery window for your normal delivery priority), so that you actually aren't concerned with your inventory, but your suppliers inventory.

Logistics is complicated. Having enough information to give low-inventory warnings for specific products, with specific counts for low-inventory items, is tractable for some retailers, but not others.

Additionally, the practice of doing so implies that there is little risk of supply running out for other products, so while it may motivate decisions on the products that have the warnings, a retailer being known to provide the warnings may have the opposite effect on sales of products that don't have the warnings. So it may not always be a win to do it.

I'm not in the online retailing market, but I'll hazard a guess anyways.

It's a combination of things you guessed (pricing tricks/marketing) at plus, real-time anything is very hard especially when you're making an offer to consumers. Goods can move quickly and purchases occur at the same time (many in fact) and it depends on the location an store house of goods. If you don't have tight controls around location, order times, and a host of other things, it's difficult to reliably give that information to an end user. I can see it being a bit easier for a warehouse only or B&M online item where the location and the product are very specific (we have 5 TVs at the DFW location) but get hairy when factoring in entire regions or product that is on various statuses but you can still deliver by a certain date. You don't want to over promise and constantly disappoint/refund customers or under estimate and not sell enough. Logistics, inventory tracking, and real-time data are hard especially all together.

Keep in mind I really have no idea what I'm talking about...

I assume that most online stores are selling from their warehouse and not their store fronts (which could be a bad guess). They also have to have the inventory numbers because items get sold out before you purchase them.

From there let's assume that they don't want to build the real-time infrastructure themselves because it is hard. They could use some like pubnub/pusher/bashoto

Some stores like Macy's actually do fill from their storefronts. They can't get realtime inventory numbers that way because they have employees go and pick off the shelf, at the same time customers are buying off the same shelf.

Notice that Amazon.com does say "Only 3 left in stock! Hurry!" when stocks are low, but they don't tell you when stocks are high.

So maybe that tactic works when they're about to run out. But the reverse is also true. If you see that a retailer has 10,000 units of the product you want, you may conclude that you do not need to rush to make a decision, and delay your purchase.

Also, competitors would love to know the inventory stats of their competition and adjust their sales tactics accordingly. For instance, if you knew that your competitor only had 10 units left of something, you may raise your price knowing that they will soon sell out and you have the market to yourself.

Yeah Amazon probably does it best with the low stock notification and I legitimately feel a pressure to purchase when I see the actual number.

The competition thing is an interesting take, hadn't thought about that.

On 淘宝 (taobao.com, the largest Ecommerce platform in China) users can see both sales volume (how many of that item did that seller sell in the last month) and inventory (how many items does that seller claim to have in stock).

I'm sure that some of the inventory numbers are inaccurate (i.e. the small retailer doesn't have 100k units of something in her warehouse) but I know that some retailers (particularly for clothing) do provide accurate inventory numbers (down to size/colour level) so that, when I am adding to my basket or checking out, I can see if I need to hurry.

Inventory is not useful. You really need available stock, which is inventory + incoming stock movements - outgoing stock movements. This can be expensive to calculate (for a catalog page of 20 items), and stored in a different system to the e-commerce system. So, page load time as a metric may be more important. You might even find they have already tested this and get more sales without it.

On the tech side there's definite things that you could do to get around that and I'd expect some sort of real-time communication would be necessary to track all that stuff, but there are companies that handle that sort of thing pretty cheaply like pusher/pubnub/bashoto.

I'd be surprised if they get more sales without it, if they are only showing available stock values when they are below a certain threshold, say ten items.

You didn't ask if there was things to do to get around it, or if you would be surprised, you asked if there was a specific reason :)

Big companies don't want "pretty cheaply" they want "logistics systems that you don't get fired for purchasing".

Inventory numbers are also an irrelevant metric when it comes to how long an item is going to stay in stock.

New items come in all the time, so what might be 3 in stock this minute may be 103 the next.

Also, depending on the item, 12000 in stock right now might be zero in one second if there's suddenly a run on it.

But as a consumer, I am more likely to purchase if I see that the inventory is low vs if there is 12000 available even if there is the same chance of it selling out before I checkout.

Seems to me that the best tactic would be to only show inventory numbers when it's below a certain threshold or the velocity of the inventory is decreasing sharply.

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