Posts Tagged ‘bias’

What’s so bad about bias?

August 13, 2020

The dictionary definition usually goes like this:

biasn. inclination or prejudice for or against someone or something (a person or group, or an opinion, or a theory, ……). v. incline, or cause to be inclined, in favour of someone or something

Unbiased brain image

A preference for anything is a bias. A preference for a particular food, or person, or pet, or idea is a bias.  Animals too exhibit behaviour which humans would interpret as bias. A bias is clearly a cognitive state based on the knowledge, memories and values stored in that brain at that time. It is also clearly a dynamic state and changes as the state of the brain changes. Consider a brain fully capable of thinking but empty of all memory, all values, and all knowledge. A brain with no preferences for anything! Such a brain would begin as truly unbiased when required to form an opinion. An impossible state, of course, but useful as a thought experiment for defining a zero bias condition.

A preference for anything is, in fact, the result of a cognitive judgement made by a brain based on the knowledge and memories it has and on the internal value scales it uses. Our empty, thinking brain could not form an opinion about anything without first having some knowledge and some value scale to apply. Forming an opinion, is itself, the creation of a preference and a bias. Expressing an opinion is an expression of bias. All knowledge is bias. The greater the knowledge held by a brain, the greater the bias it has. The clearer the set of values held by a brain, the greater its bias. An unbiased mind is an empty mind.

Bias, itself, is not a value. It is, I think, a description of a cognitive state. A knowledgeable person, a person with opinions, is a biased person.

A learned judge is a biased judge. An unbiased music critic with no prior opinions is a useless critic. A food critic without taste preferences would be unbiased but would also be worthless as a critic. Unbiased parents would show no preference for their own children. Without bias, “good” and “bad” start with equal value. I am incurably biased against what I consider “bad” and against people I don’t like. Bias is merely the current state of a functioning brain.

Yet, bias is considered “bad” and to be unbiased is considered “good”. I suspect it is because we conflate the state of bias with the value scale of fairness.

But bias and fairness are entirely different things.


Animal studies biased to give “positive” results

July 18, 2013

It is not suggested that the bias is any form of deliberate misconduct but a new paper shows that animal studies are subject to an “excess significance bias”.

Tsilidis KK, Panagiotou OA, Sena ES, Aretouli E, Evangelou E, et al. (2013) Evaluation of Excess Significance Bias in Animal Studies of Neurological Diseases. PLoS Biol 11(7): e1001609. doi:10.1371/journal.pbio.1001609

Author Summary

Studies have shown that the results of animal biomedical experiments fail to translate into human clinical trials; this could be attributed either to real differences in the underlying biology between humans and animals, to shortcomings in the experimental design, or to bias in the reporting of results from the animal studies. We use a statistical technique to evaluate whether the number of published animal studies with “positive” (statistically significant) results is too large to be true. We assess 4,445 animal studies for 160 candidate treatments of neurological disorders, and observe that 1,719 of them have a “positive” result, whereas only 919 studies would a priori be expected to have such a result. According to our methodology, only eight of the 160 evaluated treatments should have been subsequently tested in humans. In summary, we judge that there are too many animal studies with “positive” results in the neurological disorder literature, and we discuss the reasons and potential remedies for this phenomenon.

Roli Roberts writes at the PLOS blog:

But a study just published in PLOS Biology by Konstantinos Tsilidis, John Ioannidis and colleagues at Stanford University shows that a meta-analysis is only as good as the scientific literature that it uses. That literature seems to be compromised by substantial bias in the reporting of animal studies and may be giving us a misleading picture of the chances that potential treatments will work in humans. ….

Rather than wilful fraud, the authors of the PLOS Biology study suggest that this excess significance comes from two main sources. The first is that scientists conducting an animal study might analyse their data in several different ways, but ultimately tend to pick the method that gives them the “better” result. The second arises because scientists usually want to publish in higher profile journals that tend to strongly prefer studies with positive, rather than negative, results. This can delay or even prevent publication, or relegate the study to a low-visibility journal, all of which reduce their chances of inclusion in a meta-analysis.

The new work raises important questions about the way in which the scientific literature works, and it’s possible that the types of bias reported in the PLOS Biology paper have been responsible for the inappropriate movement of treatments from animal studies into human clinical trials. What do we do about it? Here are the authors’ suggestions:

  1. Animal studies should adhere to strict guidelines (such as the ARRIVE guidelines) as to study design and analysis.
  2. Availability of methodological details and raw data would make it easier for other scientists to verify published studies.
  3. Animal studies (like human clinical trials) should be pre-registered so that publication of the outcome, however negative, is ensured.

 Well, these are all excellent, but most people would also say that there are problems elsewhere in the system – in the high-profile journals’ desire to a have a cute story with well-defined conclusions, and in the forces exerted on authors by institutions and funding bodies to publish in those high-profile journals.

Paywalls are a real turnoff

July 21, 2010

Over the last few weeks I find I am just not visiting The Times site any more. Clearly I am not the only one as Business Week reports. After 42 years of reading The Times regularly, I find I don’t miss it much either, which I thought I might. In fact there is not a single reporter or columnist at The Times who can any longerbe classified as a “must read” . Their speed of reporting has been insufficient to lead to any scoops and their biases are not insignificant. Lately they have shown little editorial courage either. Perhaps their time has now gone.

Visits to the website of The Times newspaper have fallen to a third since Rupert Murdoch’s News Corp. started asking users to pay for online access. Traffic in the week ended July 10 declined to 33 percent of that before the company demanded users register, according to data compiled by Experian Hitwise. The Times’ share of traffic to news and media websites from the U.K. fell to 1.43 percent from 4.46 percent, Experian said in an e-mailed statement.

In fact blogs even with their blatant partisanship are getting more of my visits than the Mainstream media sites. The known political slant of the blogs can be easily discounted but the MSM which claims impartiality is becoming less reliable because they are all actually quite biased but their bias is not visible.

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