Health Services as Credence Goods: a Field Experiment (2020)

One of the stupidest decisions in life I made after moving to first world country was using my privilege of dental insurance.

I did go to a dentist in India(my home) Dentist said nothing wrong just floss. Then I had moved to berlin and hey I have insurance now for dental check ups.

The first visit resulted in 4 fillings. One filling was bad resulted in root canal. That root canal went bad and the other molar needed root canal.

I took my x rays from first and second dentist to dentist in India, where he told I did not needed those fillings.

At this point I have zero trust in any doctor in Berlin, I get my check ups done in India.

I also did not save any money from my adventures in Berlin, Because every visit resulted in doctor offering a better choice which is not free under insurance and this ended up way costlier than the whole process in my home country.

My wife never had a cavity in her life. We moved to a new state/city and the dentist she tried “found” 4 cavities. We went to another dentist, found none. To this day nearly 10 years later the entire family goes to the 2nd dentist and couldn’t be happier. Long after leaving the first practice their office would occasionally send out promo emails offering sale prices for services. Greedy unethical people exist in all professions.

Edit: Thinking about it further (it has been almost 10 years) I had also gone to the first disreputable dentist around the same time as my wife's initial visit because I cracked a tooth (furthest back lower mollar on one side). They extracted it and wanted to put in a dental implant to the tune of several thousand dollars. Nothing particularly nefarious so far, except that they kept pressuring me about the implant because without it, the corresponding upper tooth would start coming down due to not having a tooth to match up with below it. I didn't do it, partly for the money and partly because I'd heard implants were painful. It doesn't affect my smile or my ability to chew/eat. 10 years later the upper molar hasn't budged one iota.

Oh boy.

Years ago I visited my home country with my partner. She used to prefer going to dentist there, old habits I guess. On this particular trip I agreed to a check up as well - It had been a while since I had my teeth checked, why not?

Really fancy dentists. Big offices, flashy machines, everything looked pristine. X-rays are taken, teeth are checked. Result: You need root canal! You should have it done soon, it's going to get much worse and hurt a lot more! We can do book you in ASAP.

Hollllld on. I was on holiday, I'm not about to have a root canal procedure done and ruin my time off. I'll take the xrays and check back with a dentist back home.

I pay dearly for the check and xrays and proceed to not enjoy my time off as much as I could have - I was worried.

Fly back home, book a session with my usual dentist. "I can't see anything wrong with this tooth. But let me do an xray as well... Nope. Can't see anything wrong."

It has been around 5 years now. That dentist would have performed root canal on me for no apparent reason...

One really interesting conversation I had with my usual dentist:

Me: So really, nothing wrong? Why would they say otherwise?

Dentist: Nothing wrong. I'm not sure why they told you otherwise.

Me: That's just...

Dentist: Tell you what, they say it's this tooth points, right? Do any other of your teeth look different in the xray? Check the root as well, pay close attention.

Me: I don't see any difference, but I'm not a dentist...

Dentist: Well, I am a dentist, but I also see no difference.

Fifty of the dentists find at least one 'cavity', some of them up to six. 'Cavities' were found in up to 13 different teeth. Socio-economic status of the patient is relevant in how many times 'cavities' are found.

If you ever have a long layover in Bangkok be aware that there are plenty of very professional reputable places that offer a proper tooth cleaning for ~$50.

They don't view you as a repeat customer, ask for an opinion on your way out. I'm quite sure they never bullshitted me once and I say this as a notorious anti-dentine.

Several other places I can recommend trying this: Lima (Peru), Buenos Aires, Israel.

I have no idea why that is exactly but I assure you that you would not be compromising on the quality of the care. Quite the opposite.

I find the re-naming of this post quite weird. The original title "A patient without cavities visits 180 dentists" was informative, and made me click. The paper is about that exact thing, and I enjoyed it.

On the other hand, I have no idea what "Health Services as Credence Goods: a Field Experiment" means. With this title, I would definitely not have clicked the link. I know it is the title of the paper, but given that HN is not an academic journal, it should be allowed to give more informative titles to posts than the original content.

I trust dentists about as much as I trust car mechanics. I'm sure I've had stuff done that was marginal at best and has now caused further issues.

If anyone is wondering why poor people were targeted more, I'd hazard an educated guess on some of the "complex" factors:

1. The poor are less likely to seek a second opinion.

2. And, less likely to be able to sue. The near complete lack of accountability might even be the main reason.

3. Some people associate how much money you make with how 'worthy' a person you are. There are likely quite a few dentists who quietly 'justify' unnecessary treatment based on that line.

People don't seem surprised that 50 out of 180 dentists would fuck up your teeth for money - because we know what dentists are like, and many of us share similar experience. I certainly do. I have some kind of nerve damage from a shitty dentist, was recommended unnecessary fillings and root canals, etc.

50 out of 180 isn't a normal error rate - it's the mark of a broken industry, crying out for overhaul and accountability. Where are the "good" dentists speaking out on this? In my experience even the good ones make excuses for the shysters.

I used to go to the dentist every 4-6 months and there was almost always something that seemed to require a drilling procedure. Then after graduation my life became chaotic and I stopped going and frankly haven't been to the dentist in seven years. So far I've felt no toothache or anything like it. I know I'm probably walking around with a host of dental problems. Still seems interesting that I've made it this far.

Is "cavity" one of those things that develop gradually and it's impossible to draw the line when exactly you have one and when not? Is it possible that some of these dentists just have differing opinions on where the line should be drawn?

I used to have a lot of cavities due to poor oral hygiene, after I had a complications with my wisdom tooth, I really decided to step up my game and take care of my teeth. Brush 3 times per day, 15 minutes after every meal. Floss two times per day. Reduce soda intake. Reduce sugar intake.

Cavity free for 4 years now. I switched dentist and after several visists she accused me of seeing another dentist because I didn't have any new cavities. Anyway ...

Everyone talks about the dentist topic. To me, what this points to is much bigger: Expert knowledge is greatly overrated and researcher-subject effects (biases) are greatly underrated. Heterogeneity of results in many fields that deal with humans suggests that triangulation (a concept known in the social sciences - e.g. to use many data source, many approaches and many opinions) is perhaps the only solution to offset human subjectivity.

Sci-hub link: https://sci-hub.se/10.2139/ssrn.3036573

This happens in the UK as NHS dentists get paid based on work done. My old one before I moved was great, regular checkups and no issues. Moved house and my new dentist 'found' 4 caveties that all needed fixing, one of which was 'critial'.

Me being stupid agreed to have the main one done, which they botched and it turned into a root canal. Swapped dentists after that and went private and magically I have no cavities and they couldn't understand why I'd had a root canal.

Fuck dentists.

My first memory of going to a dentist was the school dentist (in the Netherlands); they said I had a cavity. I was small so I started shouting (when a needle came out) that I wanted my mother; she came and told them to keep their hands off of me. Our family dentist (an uncle) said I have no cavities and don't go to other dentists if I value my teeth. 43 years later I have 0 cavities while dentists in several countries and locations told me I have. I always get at least 2 opinions since that first experience. Luckily I had a total of 3 dentists in my family but they are retired now.

Think a good one (multiple people said it) is getting a cleaning; they will see if there are cavities but have no financial incentive to make them up and start drilling.

I was curious how the High/low Socio-economic status would have played out in Methodology:

> To indicate a higher socio-economic status, the test patient wore a high quality suit and high-end accessories such as an expensive watch, a car key and a new and expensive mobile phone. The test patient specified his occupation as a translator at a bank when asked to fill out the patient form.

> In the lower socio-economic status role, the test patient wore cheap unbranded clothes, an old backpack and had no accessories. The test patient declared to be a student of translation doing an internship.

> Note importantly that in both socio-economic status-roles the patient signals to have studied. Hence, the level of education was kept constant across the two conditions.

Very readable/accessible article. This finding caught my eye:

> Regarding the treatment—the test patient has a superficial interproximal caries lesion that should not be treated by an invasive treatment such as a filling—the suggested number of fillings at dentist ranges from one to six. Moreover, we observe that 13 different teeth to be treated with a filling appear across all cost estimates. Thus, besides our finding of a considerable overtreatment recommendation rate, we also observe a striking heterogeneity in the treatment recommendations.

Incredible research! I have had this intuitive feeling for a long time, that the more I go to the dentist, the more issues appear. And when I recently shopped around for different dentists, they all had completely different recommendations for the same situation.

> Dentists with shorter waiting times are more likely to propose unnecessary treatment.

Does this mean that dentists who are better at dentistry (and as a result have more patients) are less likely to propose unnecessary treatment because they know better? Does it mean that dentists who have fewer patients (and are therefore more desperate for money) are more likely to propose expensive treatment?

God I hope those dentist lost their medical license forever. I am very untrusting of dentist in general due to issues like this. I remember my brother as a preteen had 6 teeth removed and my mom said she didn't think he needed it but she was trust the doctor always type. Later the doctor was found to be pulling teeth of kids on state insurance that didn't even have cavities.

The best option is to opt for a prepaid package with all things included. Then it's not in their best interest in seeking cavities were there are none. Still they couldn't ignore any real one one if it needs attention - leaving it as it is would lead to much more expenses in the future, so they would nip it in the bud.

But I don't understand, don't they do imaging work during diagnosis?

Here in Chile, this is usually free with the first diagnosis in private clinics, as a way of getting your business. Plus it's pretty popular to license this software called Dentalink here, which has a patient log complete with graphics on which part of what tooth was treated or if it was just an estimate given and it's pending treatment.

One caveat is that the clinics that do free diagnosis + x-rays don't hand them to you as part of the deal, but you can ask to get them e-mailed. Smaller practices without their own machines just give you an order to an imaging center, those are always yours to keep.

I've had pretty consistent results (and estimates) between the big retail practices for standard dental work like cavities. Some tried to upsell on the cleaning and whitening, but it's not a big difference.

At one time I was living in a very nice apartment, and the building next door had a private dentist. Absurdly expensive, but convenient. So I got a toothache and booked an appointment for the next morning, but the next day my toothache was gone. After taking the x-ray and examining it with me the dentist asked me which side the toothache was on. For some reason I said the left. He pointed at the left side of the x-ray and explained why I needed a filling. Then I remembered it was the right, and corrected myself - he looked at the x-ray again and started to explain why I needed a filling on the right side.

I left in disgust and haven't had a toothache in the ten years since.

Dentists have a trick where they show your old fillings on the intra-oral camera and say the “yellowing” means it’s gone bad and recommend refilling it.

If your dentist pulls this trick, leave immediately.

In the US, there were several recent scandals of dentists purposefully cracking molars to get business.

Talking about dental care:

Almost a year ago, I had a wisdom tooth removed. I still feel some pain. So I went back to my oral surgeon. He did a 3D-Scan and said the bone has not regenerated. So there is a hole, where the tooth was. His suggestion is to:

A) Do the operation again. And remove all the tissue that is where the tooth was.

B) Fill the hole with a blood clot generated from some of my own blood, taken from my arm.

C) Hope the bone will then regenerate.

I have put a lot of time trying to find something about the situation on the web. But to no avail.

Any ideas how to find something about the situation that a bone does not regenerate after a wisdom tooth removal?

The surgeon said it happens to one or two of his patients per year. So worldwide, there should be tens of thousands of people having this issue every year. Yet I cannot find anything. Is my Google-Fu lacking?

Here is the full text and pdf

https://www.researchgate.net/publication/320070183_Health_Se...

Question: what is a credence good?

Also:

> Dentists with shorter waiting times are more likely to propose unnecessary treatment.

I’m admittedly focusing on the narrow end, here, but this is intriguing. How large is the effect? I couldn’t access the full paper.

Intuitively, this would suggest that certain dentists are optimizing for low-effort, high-margin procedures. If that’s the case, I’d expect the distribution of wait times to be multimodal, which might offer a path to detecting such practices cheaply.

This is something that should be done regularly by health insurers. And maybe even by some sort of government agency that supervises the health industry.

It's expensive to be poor.

When I lived in the UK I went to a dentist who recommended to treat 5 or 6 cavities. I only wanted a check-up as I planned to fix anything in Poland which I regularly visited. There I heard that only 2 were actually something worth taking care of. I thought maybe different countries have different standards for what needs attention.

One thing they should check is of the dentists that were committing fraud had anything in particular in common, like religion or heritage? Some religions teach that other people are subhuman and made to serve them in particular and see no issue commiting fraud against certain groups of people.

It's really a shame on many axis:

- what about the hippocratic oath ?

- how come there are so many errors ? where are quality checks in this field ?

- how come this is not regulated business wise ? dental care costs a lot, it puts people in dire situations

are we waiting from a uber teeth to force these people to work properly ?

This is depressing to see and confirms what I thought. We recently went to see a family friend dentist and they just did one small touch-up and a clean-I hadn't been to the dentist in a few years and was expecting a load of issues.

I’m in the UK and lucky to be registered with an NHS dentist (places are scarce) so they have no incentive to treat problems I don’t have. I have to pay a token amount for dental checks and hygienist visits. Something like £15 a time.

About to hit the 5 year anniversary of being told I need an urgent root canal.

Fortunately, buying a softer toothbrush fixed the issue - I would have paid them $1,000 to get that recommendation a few weeks earlier!

I'm really not surprised. My recent dentists have all been really good, but growing up we had one that would want a drilling procedure every time. I'm glad we switched when we did.

I would say 28% is not that bad. Of course ideally it should be 0%.

But thinking about normal distribution of skills I can imagine 20 to 30% dentists not being that competent should be well normal.

I've been following a method where every year I see a different dentist and I only get something fixed if two subsequent dentists diagnose the same issue.

Firstly I'd say that although there are 180 dental practices, there is only one patient, I think a study would need a lot more than that. I cannot read the article but at how many practices did this person have x-rays taken? I doubt it was many if any. How did they get out of that, by bringing their own x-rays with them and saying that they were a recent set from their last dentist who'd retired? If they didn't have x-rays taken and didn't bring any with them then the dentist would be diagnosing blind to a large extent. In any case diagnosing cavities is not a binary true/false affair and x-rays can mislead also. There is a lot of human judgement involved. Some cavities never need filling, others can increase massively in size over a short period. Two questions that a dentist will typically ask a new patient are, how long since your last attendence at dentist and are you a regular attender or do you just go when you have problems? If a new patient is a regular attender, a dentist will be happier to keep a cavity they are unsure of, under observation. Sometimes they may schedule shorter recall periods for review until such time as they are comfortable that the patient does not have active decay. Generally a cavity does not need to be filled unless it extends into dentine. Determing if this is the case is not always straightforward. Generally a filling does not need to be replaced unless it is leaky. Again this is not always easy to determine and like programmers, dentists tend to be more critical of other dentists' output than their own. Recent experience also colours judgement. If a dentist has had a run of cavities that turned out to be deeper than expected then they are more likely to diagnose a cavity when unsure and vice versa. Different sub-populations in the aggregate, depending on wealth, diet, dental hygiene and typical frequency of attendence have different dental decay characteristics which can colour a dentist's judgement. There are crooked and incompetent dentists just like there are in every job. Dentists in general get a bad rap. One reason I've heard is the fear of dental treatment breeds an instinctive, subconscious dislike and mistrust of dentists as persons. Certainly doctors, despite being equally good at extracting money from their patients don't suffer from the same degree of antipathy and suspicion.

I wonder if capitation and managed dental care would help mitigate over utilization of dental services. It seems to be working in the medical field.

But did they see this guy?

https://m.youtube.com/watch?v=YoWom0CCRKM

This right here is why all healthcare, including dentistry and optometry, should be nationalised.

When I was in the US my dentist said I needed to go every 3 months for some special cleaning that cost more $$ and that I have gum disease. Now in Thailand I go every 6-12 months for a normal cleaning and they say everything looks just fine but that maybe I brush a little hard

In the US, anyway, you should always get a second opinion.

Clearly the work of rabid anti-dentites.

Bullet point 1: at 35 years old, I hadn't been to a dentist in 12 years; walked into a clinic in Spain for a cleaning, and the lady gasped that I had no cavities and no missing teeth. I only brush once a day, without toothpaste.

Bullet point 2: No one on my father's side has ever had a cavity that I know of. We do all get kidney stones. I think it's related.

Bullet point 3: I went for a routine cleaning after I moved to Portland, OR (age 38), and was told I had two cavities. I stupidly believed the man. He drilled and filled them. It was the night before Christmas Eve, when they were having their holiday party. I think he was drunk. His nurse was definitely drunk. All fun, and such, until both teeth split in half around the fillings, exposing the nerve (the first on New Years Eve, 9:30 at night; try having emergency dental work done then).

I thought about suing him. Who knows; I've never had a cavity since then, and it was 6 years ago, but I'm missing two teeth.

And yes, I've decided against firebombing his office. Consciously. Every year on new years.

Not related to this topic, but I am curious how the situation looks like in IT industry. Say a company without any "real problems" ask for "advice" 180 IT agencies. My guess that situation will be much worse.