Comparative expense in grocery shopping

Apparently, people like to eat.

Moderators: SecondTalon, Moderators General, Prelates

mercutio_stencil
Posts: 293
Joined: Tue Feb 02, 2010 8:36 pm UTC

Comparative expense in grocery shopping

Postby mercutio_stencil » Mon Dec 10, 2012 7:57 pm UTC

I'm lucky enough to live in a town with lots of choices for grocery shopping; we have everything from a Grocery Outlet, to a local, upscale chain, to a Whole Foods, to a food cooperative. Everyone has strong opinions about their preference in stores, usually in regard to price.

Being bored, and having near endless free time, I decided to try to test some of these assumptions. The real question is should I do the comparison on individual items (ie a 12 ounce box of Kraft macaroni and cheese) or product categories (ie the cheapest box of macaroni and cheese)? When you go shopping, do you go looking for certain brands, or just a product? Well, undoubtedly, it varies, but what method should I use in this project?

User avatar
SurgicalSteel
Posts: 1926
Joined: Tue Jan 19, 2010 4:18 pm UTC
Location: DMV, USA

Re: Comparative expense in grocery shopping

Postby SurgicalSteel » Mon Dec 10, 2012 11:14 pm UTC

The best way to do it, but this would take a while and be pretty subjective, would be to set an acceptable minimum for quality and compare cheapest product at that quality level. For example: Kraft Mac and Cheese might be cheaper at Store A, but Store A brand mac and cheese is better than Store B brand mac and cheese, but still cheaper than Kraft Mac and Cheese from Store B. Store B brand mac and cheese is below the minimum acceptable quality. Store A wins in this situation.

Edit: i forgot to type the rest of my post.

The way I would do it is on a product by product basis. For products where brand is important (maybe you really really like Kraft) compare the same brand. For products where you're cool with whatever, like maybe bread or mustard if it was me, just compare the cheapest.
"There's spray paint on the teleprompter
Anchorman screams that he's seen a monster (mayday)
There's blood stains on his shirt (mayday)
They say that he's gone berserk."
--Flobots "Mayday"

mercutio_stencil
Posts: 293
Joined: Tue Feb 02, 2010 8:36 pm UTC

Re: Comparative expense in grocery shopping

Postby mercutio_stencil » Mon Dec 10, 2012 11:26 pm UTC

SurgicalSteel wrote:The best way to do it, but this would take a while and be pretty subjective, would be to set an acceptable minimum for quality and compare cheapest product at that quality level. For example: Kraft Mac and Cheese might be cheaper at Store A, but Store A brand mac and cheese is better than Store B brand mac and cheese, but still cheaper than Kraft Mac and Cheese from Store B. Store B brand mac and cheese is below the minimum acceptable quality. Store A wins in this situation.

Edit: i forgot to type the rest of my post.

The way I would do it is on a product by product basis. For products where brand is important (maybe you really really like Kraft) compare the same brand. For products where you're cool with whatever, like maybe bread or mustard if it was me, just compare the cheapest.


While I think this does best reflect how we (or at least I) actually shop, it still relies on the subjective perception of quality, and a personal judgement on what's 'worth it'. I was hoping to avoid that much subjectivity.

I could use myself as a model and hope that my tastes reflect the average population, which seems like a poor assumption to make. I would also recruit friends as a comparison, but that seems awkward (socially).

Maybe a reflection of the spread of prices across a product category, with a min/max, average and standard deviation. It would mean I would have to take even more awkward notes in the supermarket though.

Роберт
Posts: 4285
Joined: Wed May 14, 2008 1:56 am UTC

Re: Comparative expense in grocery shopping

Postby Роберт » Tue Dec 11, 2012 4:14 pm UTC

I wouldn't use the max price in the metric at all. Than you take a hit for offering more options.

I would probably go with (namebrand+cheapest)/2 or something like that.
The Great Hippo wrote:[T]he way we treat suspected terrorists genuinely terrifies me.

User avatar
Adam H
Posts: 1267
Joined: Thu Jun 16, 2011 6:36 pm UTC

Re: Comparative expense in grocery shopping

Postby Adam H » Tue Dec 11, 2012 4:21 pm UTC

The correct way to do this is to do both. :P

Your results might give you something like "Store A has the cheapest generic mac&cheese, while Store B has the cheapest Kraft mac&cheese."
-Adam

User avatar
Bakemaster
pretty nice future dick
Posts: 8915
Joined: Fri Jul 06, 2007 2:33 pm UTC
Location: One of those hot places

Re: Comparative expense in grocery shopping

Postby Bakemaster » Thu Dec 13, 2012 1:36 am UTC

mercutio_stencil wrote:I'm lucky enough to live in a town with lots of choices for grocery shopping; we have everything from a Grocery Outlet, to a local, upscale chain, to a Whole Foods, to a food cooperative.

Not to mention Trader Joe's, two Safeway locations, the year-round farmer's market, Westlake IGA...

Have you seen the big price comparison board at Nugget? Is that what started you thinking about this? Because if not, go into Nugget and ask them about their price comparison thing. I find their results pretty questionable, but I haven't been there since the Whole Foods opened, and I think it's mostly a matter of them being very selective with their exact inventory—a lot of the "same" stuff, they must carry in a more expensive brand, because ain't no damn way they're the cheapest game in town the way the board implies.
Image
c0 = 2.13085531 × 1014 smoots per fortnight
"Apparently you can't summon an alternate timeline clone of your inner demon, guys! Remember that." —Noc

mercutio_stencil
Posts: 293
Joined: Tue Feb 02, 2010 8:36 pm UTC

Re: Comparative expense in grocery shopping

Postby mercutio_stencil » Sun Dec 16, 2012 9:21 pm UTC

Bakemaster wrote:
mercutio_stencil wrote:I'm lucky enough to live in a town with lots of choices for grocery shopping; we have everything from a Grocery Outlet, to a local, upscale chain, to a Whole Foods, to a food cooperative.

Not to mention Trader Joe's, two Safeway locations, the year-round farmer's market, Westlake IGA...

Have you seen the big price comparison board at Nugget? Is that what started you thinking about this? Because if not, go into Nugget and ask them about their price comparison thing. I find their results pretty questionable, but I haven't been there since the Whole Foods opened, and I think it's mostly a matter of them being very selective with their exact inventory—a lot of the "same" stuff, they must carry in a more expensive brand, because ain't no damn way they're the cheapest game in town the way the board implies.


I haven't actually been to the Westlake IGA for anything, let alone price comparisons. It's just so far out there.

My initial research actually shows that the local food co-operative is cheaper on average for a given brand, and only slightly more expensive than Safeway for a given product category. Across the board, the Nugget is the most expensive, both by brand, and by product category, and Whole Foods comes in just slightly lower.

I have no idea how the Nugget comes up with their price comparison board. My research now says it's probably wrong, or at least misleading.

The real question is about sampling artifacts, because my initial product list is shaped by my grocery purchases, and I tend to shop at the co-op, am I just purchasing things that are cheap at the co-op and expensive elsewhere.

I suppose the question is, what products (or product categories) should I sample to try to remove my bias? Or put another way, what do you shop for?

User avatar
Bakemaster
pretty nice future dick
Posts: 8915
Joined: Fri Jul 06, 2007 2:33 pm UTC
Location: One of those hot places

Re: Comparative expense in grocery shopping

Postby Bakemaster » Sun Dec 16, 2012 10:10 pm UTC

There are a lot of directions you could take in developing meaningful product categories. The weakness of that approach, I think, is that it would internalize the experimenter's bias from the very start of data collection. For example, I started trying to think of some kind of generic WASP nuclear family shopping list, and I can barely get past "milk, bread, eggs" before I start feeling like I'm making too many assumptions; do I put bacon on the list? Cold cereal or oatmeal or bagels? What goes on the bread—peanut butter and jelly, or lunchmeat? Do I put them both on the list?

I think any approach has the potential for an interesting end result, but you seem to be looking for more than just "interesting" - it sounds like you want to maintain some level of scientific or academic rigor. Correct me if I'm wrong. In which case, you would probably want to base your categories on reasonably current public data or published research.

Like I said, Nugget employees will tell you about their price comparison thing if you ask. If I recall correctly, they give out surveys, you go to another grocery store and you pick items and write down the price and the item. Not sure if you identify it by UPC or by brand and product name or what. Then you bring it back to Nugget and they check it against their product list. I asked what they do if there's a product they only carry in another brand, and the cashier I was talking with said they have to compare the exact same product, same brand, size, flavor, etc., or the data point is discarded.

I don't know whether they manipulate the data by undercutting their competitors for these specific items as the surveys come in and recording the altered price instead of the previous price. That would be pretty unethical. Other possibilities are that they simply don't carry a lot of brands that other stores carry, and they make sure that the brands they *do* share with other stores, they sell cheaply. Then they make their profit off of more expensive brands that don't appear in other stores. I think this is plausible. If you've ever tried to test a "price match guarantee" for example at an electronics store, you'll notice that often times two different chains will carry completely different product lines, so they can both offer this guarantee and still not have to match their prices for what are essentially the same items.

You're going to have trouble comparing the co-op to the other stores because of the number of items that can only be found at the co-op. I really doubt the items that can be purchased at both the co-op and a supermarket are an unbiased subset of all the items the two stores sell.
Image
c0 = 2.13085531 × 1014 smoots per fortnight
"Apparently you can't summon an alternate timeline clone of your inner demon, guys! Remember that." —Noc

User avatar
sardia
Posts: 6456
Joined: Sat Apr 03, 2010 3:39 am UTC

Re: Comparative expense in grocery shopping

Postby sardia » Thu Dec 20, 2012 8:41 pm UTC

If you really cared, you'd apply a triangle test to either yourself or someone you dine with. Buy two brands of the same food, make 3 batches, and ask them which one is different or tastes better. If you can't tell, buy the cheapest/easiest/w/e metric you want. Make sure it's double blind, and you're good to go.

User avatar
freezeblade
Posts: 1270
Joined: Fri Aug 24, 2012 5:11 pm UTC
Location: Oakland

Re: Comparative expense in grocery shopping

Postby freezeblade » Thu Jan 03, 2013 11:20 pm UTC

mercutio_stencil wrote:I'm lucky enough to live in a town with lots of choices for grocery shopping; we have everything from a Grocery Outlet, to a local, upscale chain, to a Whole Foods, to a food cooperative. Everyone has strong opinions about their preference in stores, usually in regard to price.

Being bored, and having near endless free time, I decided to try to test some of these assumptions. The real question is should I do the comparison on individual items (ie a 12 ounce box of Kraft macaroni and cheese) or product categories (ie the cheapest box of macaroni and cheese)? When you go shopping, do you go looking for certain brands, or just a product? Well, undoubtedly, it varies, but what method should I use in this project?



I shop at many of these different places, for different things. I know which stores are cheaper/better quality for certain items. Example:

Grocery Outlet: Crapshoot, I head here first to see what they have at that time. It's kinda like a Ross, but for groceries. Good cheap finds here: Tea, Milk, Butter, Cheese, Sugar, Lunch/Sandwich meats, Eggs, olive oil, Booze.

Trader Joe's: Flour, eggs, milk, butter, cheese, booze. (if Grocery outlet didn't have them). Coffee.

Rainbow grocery, Piedmont market, Berkley Bowl(!): Specality flours, sugar, produce, meats, nuts

Ranch 99(Asian supermarket): Rice, peanut oil, sauces, asian-y stuff.

Farmer's Market (only on saturdays): produce, honey, heavy cream (for making butter)

There is some overlap, and I plan out my trips to make the most efficiant use of time/gas for the items I want/need. Trader Joe's and the farmer's market are a stand-by because they are walking distance, Safeway is closest and open the latest, but they are a last resort. I never go into whole foods, as the parking is a nightmare, and it's pricey for items I can get elsewhere.
Belial wrote:I am not even in the same country code as "the mood for this shit."

User avatar
Biliboy
Posts: 283
Joined: Tue Jun 24, 2008 6:43 am UTC

Re: Comparative expense in grocery shopping

Postby Biliboy » Thu Mar 21, 2013 12:33 am UTC

The answer, of course is Aldi. Assuming you have one.

Bag your own, single selection, low prices, and actually decent quality.


Return to “Food”

Who is online

Users browsing this forum: No registered users and 5 guests