Something i've been pondering for a while..

Maybe vanity sizing also has something to do with this. In a lot of brands I am a small (or extra-small) but I know there are girls much smaller than I...so what do they buy? I've noticed since I lost weight (went from always buying mediums/larges to smalls/extra-smalls) it is harder to find items...
 
I think some stores buy stock to accomodate what they sell the most of. If they're selling more larger sizes then they'll stock more of those.

One of my local shopping centres tends to have a wider stock of small sizes and when you go to the make up stores they never have my skin tone foundation etc because the shopping centre has a mostly asian consumer.

I've never understood the whole vanity sizing thing. If everybody goes down a size due to "vanity" sizing then surely your all back to the same position :shrugs:
 
It's also just what you notice. If you tend to buy smalls you're going to notice when there aren't many. If you tend to buy larges you'll notice when there aren't any of those. Think of it this way---when you go to the grocery store you may always think you choose the longer/slower line, but that's because you'll always remember when the line took forever. It's rare for a person to remember all of the times that the line went quick. So if you relate that to shopping, you'll remember the times that your specific size was out, but it's not going to stick out in your mind when you went to a shop and they had an abundance of your size.

I actually read a book a while back called The Drunkard's Walk---it's all about randomness in our world/lives. But one of the things that really stuck out to me is how you recognize one thing (i.e. never having your size at a store), simply because it relates to you, when in reality it may not "always" be that way.
 
It's also just what you notice. If you tend to buy smalls you're going to notice when there aren't many. If you tend to buy larges you'll notice when there aren't any of those. Think of it this way---when you go to the grocery store you may always think you choose the longer/slower line, but that's because you'll always remember when the line took forever. It's rare for a person to remember all of the times that the line went quick. So if you relate that to shopping, you'll remember the times that your specific size was out, but it's not going to stick out in your mind when you went to a shop and they had an abundance of your size.

I actually read a book a while back called The Drunkard's Walk---it's all about randomness in our world/lives. But one of the things that really stuck out to me is how you recognize one thing (i.e. never having your size at a store), simply because it relates to you, when in reality it may not "always" be that way.

probably true.
 
I think it's a lot of factor's, all mentioned. Depending on the store and most importantly the economic target customer. Vanity sizing for the higher end customer, possibly more mature. Smaller sizes going quicker in lower end, lower economic target(no pun) customer stores. Possibly smaller sizes going quicker, or more unfairly not being stocked, in trendier stores. And probably another million marketing factors we'll never know anything about!
 
I don't shop in juniors department or in stores like H&M, Forever21, etc. but I still find that size 0 - 2 (xs - s) are always the first to go especially in the savvy department at Nordstrom or Hugo Boss! The SA's always have to order in the small sizes from other stores which is a bit frustrating to try on something that doesn't fit and then imagine how it looks like if it does fit and then order or transfer it in. Though SA's told me they don't stock up on xs-s and only carry a couple of them because they have a lot more customers who wear medium or large.