Comments on: The Reliability Bell Curve: What Does “More Reliability” Actually Mean?

By: kcdesi

kcdesi — Thu, 14 May 2009 21:32:33 +0000

I full agree with lanhsin on this. Technology improvement is a big point to consider especially in electronics. I would rather buy a short life product for a cheaper price than a very long life product for a very large price!! That way I can get the latest technology product more frequently.

KCDesi

By: Eric

Eric — Thu, 14 May 2009 17:17:58 +0000

Love the article Trent. Brings out the economist and love of graphs in me!

By: littlepitcher

littlepitcher — Thu, 14 May 2009 13:48:09 +0000

Shauna knows her appliances and can be relied upon. Best choice is the factory store and/or scratch and dent if you can afford that. The newer energy efficiency ratings make new a bargain when you factor in savings on electric and water bills.

That said, I’ve always done well purchasing from moving sales, especially if you live in a military base area where folks transfer frequently. If you are short on cash, your employment is insecure, and your landlord supplies water and/or lights, get the used article and check websites for instructions on changing belts, hoses, and other ephemera.

By: Katie

Katie — Thu, 14 May 2009 04:51:40 +0000

Jimbo – If you bought a cheap machine, invested in this market, and had your machine break, you’d be kicking yourself for letting your money depreciate so quickly. Investments that beat inflation are never guaranteed.

By: Sharon

Sharon — Thu, 14 May 2009 04:16:50 +0000

My mother is still using the Maytags they got in 1965. They certainly don’t make them like that any more! Dad had to do some minor repairs, but if mine die and Mom moves, I’m taking them!

By: Shauna Redmond

Shauna Redmond — Wed, 13 May 2009 19:43:43 +0000

Ah Ha! I remember now Hotpoint is GE’s low end brand. Go to the Hotpoint Webpage and click the contact button and it will lead you to GE’s Website as a pop up. http://www.hotpoint.com/

By: Shauna Redmond

Shauna Redmond — Wed, 13 May 2009 19:37:17 +0000

Ooops! I guided you wrong, Estate is Whirlpool not GE. But the facts remain the same. Same product different face plate.

By: Shauna Redmond

Shauna Redmond — Wed, 13 May 2009 19:32:24 +0000

I beg to differ being a former kitchen sales rep. The “cheap” machine often is simply the more expensive machine with a different face plate. They are made in the same factory on the same assembly line with the same parts and the only difference is: Drum roll please after they run 2500 GE top lines and apply the GE logo with the “prettier” front they run 5000 Estate machines and apply a less appealing face plate at the end. This is true in many scenarios. Not only do you pay more for the machine you are almost obligated to pay for the warranty on top of it to protect your investment. It is common knowledge in the industry that both machines are the same mechanically and you are simply buying a brand name.

By: Jeremy

Jeremy — Wed, 13 May 2009 17:20:43 +0000

One thing to keep in mind:

Scenario 1 — Buy a 10-year-lifespan washer at years 0 and 10.
Scenario 2 — Buy a 20-year-lifespan washer at year 0.

The average age of the washer in scenario 1 is 5 years. The average age of the washer in scenario 2 is 10 years.

There is a good chance that the washer bought at year 10 in scenario 1 is more efficient and washes better than the washer in scenario 2.

This is especially true for electronics. I would rather buy a $1000 TV now and a $1000 TV in five years than spend $2000 for a now-top-of-the-line TV and keep it for 10 years. Your time-averaged TV quality in the first scenario is almost certainly higher.

By: jc

jc — Wed, 13 May 2009 17:15:57 +0000

Bill, you’re sorta right, but the curve is never going to be a “bell” or “normal” curve. there are, under certain circumstances, curves that look a lot LIKE a normal curve (especially a weibell distribution with a shape parameter = 3) but they’re still not the classic bell curve. i don’t believe that this is a distinction that should only be under the purview of those with a graduate education, though somehow it is…..

i think this discussion should be fairly comprehensible, with a bit of patience: http://www.weibull.com/hotwire/issue14/relbasics14.htm

By: Sharon

Sharon — Wed, 13 May 2009 17:05:41 +0000

JC and Tightwadfan’s comments made me think of another (obvious?) point: I think the distribution of the failure curve is not known until the end of the lifespan of a particular model. And by that time, manufacturers will have begun producing different models with different reliabilities. So, I suspect that even manufacturers themselves don’t have complete reliability info by model (though if they did, they would certainly guard it closely, esp. for products of poor quality; this is the “market for lemon” problem from economics, in which the seller has info that the buyer doesn’t, right?)

Re Consumer reports: I think the reliability info they report is based on reader reports of problems with products by brand, but not necessarily for particular models. (Also, CR’s ratings of brand reliability depend on who responds, and these respondents may not be representative more generally of the population of purchasers of a particular item.)

Also, speaking of CR… a vacuum cleaner repairman/salesman suggeted to me that when products are highly rated by CR, their price goes up. So, you may actually pay more for a product that is well-rated by CR than for a comparable product. This guy was so persuasive that he ended up selling me a vacuum cleaner of a brand not rated at all by CR that was cheaper than the CR “best buy” I had been planning to purchase.

By: dagny

dagny — Wed, 13 May 2009 16:02:59 +0000

Engineers have a formal definition of reliabilty which has 3 parameters: mean time between failure, mean time to repair, and mean cost to repair. (“Mean” as used here is the average.)
A washing machine should not go from working well to junk in a single step, as it often can be repaired. How often it needs repair, how long it is out of service for, and how much the repairs cost are the variables to consider. When it is older it may become irreparable if the needed parts are not available. Also at some point it may become so unreliable (fails often) that it becomes better to replace it.

By: Chuck

Chuck — Wed, 13 May 2009 15:23:16 +0000

I would also like to see added in the equation the energy efficiency that a newer machine would have if you were to buy the less expensive machine and replace it after 5-10 years. By then the machine you purchase would most likely be more efficient and cost less to operate. You might come out ahead by buying the less expensive machine and replacing it later.

By: tentaculistic

tentaculistic — Wed, 13 May 2009 14:31:59 +0000

I appreciate the graphs, Trent, and the commenters who obviously got *way* more out of their stats classes than I did!

I guess the take-away message I’m getting here (from Trent’s post and comments) is: do your product research, since price tag (high or low) does not guarantee quality level; however, the trend is toward better quality at a higher price. This is good input, since I am about to replace 3 appliances (pretty much everything *but* my washer!). Thanks Trent, and thanks folks.

By: Bill in Houston

Bill in Houston — Wed, 13 May 2009 14:27:55 +0000

Oops, I goofed. I meant to say, the minima of the higher reliability curve should be elongated and tapered more.

By: Trent

Trent — Wed, 13 May 2009 14:26:04 +0000

“Well I’m sorry to be bringing “mindless negativity” to your pristine blog. You’ve succeeded, I won’t be commenting here or visiting this website anymore.”

I’ve sent your comment to the two readers who emailed me about your negativity making them uncomfortable. Addition by subtraction, I suppose.

You’re welcome to comment whenever you like, but relentless personal attacks are not welcome here.

By: Bill in Houston

Bill in Houston — Wed, 13 May 2009 14:25:19 +0000

Actually, the Bell Curve does work when calculating failure. Remember that at the very end of the curve, 100% of the appliances have failed. Now his curves were simplified to drive home a point. In reality the ends (minima) should be elongated and tapered more. The left minimum should taper all the way to 0 no matter how much you pay. The difference is that the maximum point (the highest part) shifts rightward and the right minima shifts farther right as well.

Paying more up front for higher quality means that you replace that item less often.

Jumping back to the first post: While I do read Consumer Reports, I hadn’t thought to consult a repairman. Hang on while I slap myself in the forehead. My wife and I moved into a new house last fall. The previous owner left her appliances, of which we are using until either we remodel or they break beyond repair (that depends on finances, future children, my need for high class booze and expensive socks, et cetera)Excellent idea. Thanks :)

By: Jimbo

Jimbo — Wed, 13 May 2009 14:01:15 +0000

Well I’m sorry to be bringing “mindless negativity” to your pristine blog. You’ve succeeded, I won’t be commenting here or visiting this website anymore.

By: DDFD at DivorcedDadFrugalDad

DDFD at DivorcedDadFrugalDad — Wed, 13 May 2009 13:24:04 +0000

This is a tough one– I would go and have gone with an informal survey of friends, family, and neighbors as part of my decision making process with appliances . . .

By: Trent

Trent — Wed, 13 May 2009 11:53:24 +0000

Jimbo, you are the troll and you are actively driving away commenters. I tolerate your trolling simply because, on the whole, you tend to spur more discussion, but as time goes on, you’re slipping more and more down the troll path.

Today, two readers emailed me and pointed to you specifically as the reason that they do not comment on here any more – you bring such an air of negativity to the site that they no longer want to be a part of the discussion. That hurts the entire purpose of this site.

I don’t mind criticism. I do mind mindless negativity and trolling that drives away people. I know from your comments that you know where this line is. If you keep crossing it, I’m going to start deleting comments for the sake of other readers who don’t want to participate in the negative environment you are trying to create here.