What do we do about credence goods in the marketplace of ideas?



A major theme of my master’s thesis1 was the idea that if we want to conceive of human research protocols through the framework of a marketplace, then human research protocols are something that economists would call “credence goods.”

Credence goods are products, like drug trials, whose quality is difficult for its consumers to judge.2 Markets for credence goods are marked by learning constraints and information asymmetry.3 That is to say, there are practical constraints that prevent most consumers from learning what they need to in order to make a good judgement about whether they want a product. So, while it might not be impossible for a person who wants to participate in a trial of a drug to get a medical degree to better evaluate it, it’s not reasonable to expect the market for drug trials to function properly if that’s the level at which one has to be educated in order to participate. Financial products are other examples of credence goods, and it is (generally) non-controversial that these need to be regulated in order for their markets to function.4

A popular metaphor and justification for freedom of expression is the “marketplace of ideas”—the notion that the truth will emerge from market-like competition in free, transparent, public discourse.5 Part of what makes this marketplace metaphor compelling is the idea that, over time, the best ideas will beat out their competition. The best response to bad speech is good speech. Consumers will, over time, identify and reward the best ideas, and the market itself will regulate what is expressed without the need for heavy-handed interference from the state.

Have news articles become credence goods in the marketplace of ideas?

This idea of a marketplace of ideas seems great, except that it is getting harder and harder to sift through the bad products in the news marketplace these days, and it’s taking more and more time and expertise to find the good ones. Sure, anyone with enough time and training and education can figure out when a particular news story is fabricated, but who has the time to do that?

Post-truth is the word of the year, according to Oxford Dictionaries. By some measurements, fake news stories have greater impact than legit ones:

Facebook engagements

Facebook engagements

Just today, we went from this tweet:

Original tweet

Original tweet

To this one:

It's a faaaake!

It’s a faaaake!

And before the day was even done, we came nearly full 360 back to this:

It's real!

It’s real!

For myself, I’m at the point where I don’t have the ability to figure out what’s going on anymore. I don’t even have the rubric of “common sense” to fall back on at this point. If you had shown me 4 years ago a news article that says Donald Trump is the President-Elect of the United States, I would have assumed that it came from a fake news site. There’s part of me that’s honestly still hoping this is all a prank.

Unintended consequences

As we all know, well-intended interventions into markets can have unintended consequences.6 So even though I’m frustrated by not knowing what is going on anymore, and I’m generally in favour of market regulation, I’m worried about what is going to happen next.

I don’t know what we should do, but I have a feeling that whatever backlash is coming against the “fake news,” it’s going to have exactly the opposite of its intended effect.

My fear is that any attempt to correct the trend of fake news is going to amount to censorship of the things that don’t get covered the way that they need to be through normal channels. (E.g. Youtube videos of police officers murdering racial minorities.)


The marketplace of ideas is having a market failure. How do we fix it without making things worse?


1. Carlisle B. A Critique of Phase IV Seeding Studies on the Basis of a Non-paternalistic Justification for Subject Protections in Human Research. McGill University Libraries; 2011.

2. London AJ, Kimmelman J, Emborg ME. Beyond access vs. protection in trials of innovative therapies. Science. 2010 May 14;328(5980):829-30.

3. Carpenter D. Confidence Games: How Does Regulation Constitute Markets? l. Government and markets: Toward a new theory of regulation. 2010:164.

4. Wikipedia contributors. “Credence good.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 2 Aug. 2016. Web. 2 Aug. 2016.

5. Wikipedia contributors. “Marketplace of ideas.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 12 Oct. 2016. Web. 12 Oct. 2016.

6. Wikipedia contributors. “Unintended consequences.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 18 Nov. 2016. Web. 18 Nov. 2016.


    title = {What do we do about credence goods in the marketplace of ideas?},
    journaltitle = {The Grey Literature},
    author = {Benjamin Gregory Carlisle},
    address = {Montreal, Canada},
    date = 2016-11-18,
    url = {http://www.bgcarlisle.com/blog/2016/11/18/what-do-we-do-about-credence-goods-in-the-marketplace-of-ideas/}


Carlisle, Benjamin Gregory. "What do we do about credence goods in the marketplace of ideas?" Web blog post. The Grey Literature. 18 Nov 2016. Web. 29 Mar 2017. <http://www.bgcarlisle.com/blog/2016/11/18/what-do-we-do-about-credence-goods-in-the-marketplace-of-ideas/>


Carlisle, Benjamin Gregory. (2016, Nov 18). What do we do about credence goods in the marketplace of ideas? [Web log post]. Retrieved from http://www.bgcarlisle.com/blog/2016/11/18/what-do-we-do-about-credence-goods-in-the-marketplace-of-ideas/

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