I'm guessing here, but I'd bet that studies on feed additives are largely funded by people who want to sell them, much as studies on pharmaceuticals are largely funded by the pharmaceutical industry. I certainly wouldn't trust any one study, and publication bias is a real problem, especially in studies funded by people who want to sell you something. So you really do want to see what protections there are against publication bias. For pharmaceuticals, some protections have been put in place, and we are slowly learning that a lot of medicines are not as effective as they have claimed. Quite a few studies showing this were published around 2008, and the rules for publishing pharmaceutical research have changed as a result. Here is another study from 2008:ken_sylvania wrote:In my experience, there is a certain amount of real-world "common sense" that can tend to be missing in academia. Agricultural scientists have done a lot of research and provided much helpful input to farmers to help them improve their farming methods. With just a bit of time, I'm certain that I could pull together a list of 100 different feed additives and/or changes in practice that a farmer could implement that have been shown in scientific studies to improve profits by anywhere from $0.03 - $.50 per head per day. Do the math. If the average profit increase is $.20 per method, that's an increase in profit of twenty dollars per head per day, or about an additional $7,000 per head per year. Not going to happen, sorry.
And of course, even if one medicine is effective, taking two effective medicines may have a completely different result. There could be two different medicines that each effectively treat migraines, but if I take them both, it might result in a worse migraine or in death. For feed additives, maybe one would give you an additional $.20 per head per day, adding a second might bring you back to zero, adding a third might kill the animal, adding a fourth might bring it back to life ... who knows? You really have to study the combinations.The outcome of our investigation should not be used to dispute the value of systematic literature reviews and meta-analyses in general. However, for anyone who relies on published data alone to choose a specific drug, our results should be a cause for concern. Without access to all studies (positive as well as negative, published as well as unpublished) and without access to alternative analyses (intention to treat as well as per protocol), any attempt to recommend a specific drug is likely to be based on biased evidence.
With medicine, that makes me very cautious. A lot of medicines were approved before we had the current protections in place, and very few of the studies tell you much about taking several medicines at the same time. Worse, I think there are still significant issues of bias in medical research.
Part of the problem is relying on the people who want to sell us something to fund the studies.
If you look at the previous link, it refers to studies openly funded by these companies, so we at least know who they are and what their interest is. Even then, we need protections in place.The evidence we have presented dictates that trials should be conducted by independent bodies.
Common sense suggests the same thing. Imagine the govern- ment proposed disbanding the electoral commission in favour of letting politicians count their own votes. This would not be accepted for various reasons. Politicians are not objective. They have invested time and money campaigning. They believe in their party. They want to win. The less honest politician might fabricate results. The more honest might approach the task with sincerity, but be influenced subconsciously into appraising incomplete ballot forms as valid based on their endorsements. For these valid reasons, the results would not be accepted so that would be a waste of time and money. If this is the case why is accepting the ‘vote counting’ of industry in demonstrating the efficacy of their own products any less flawed? And we do not need a thought experiment to explore whether the results are biased. Real experiments have repeatedly shown this.
One might object by noting that randomized trials are very expensive. It was perhaps thought that industry-funded randomized trials represented a happy coincidence between commercial self-interest and the public good. However, this has been a false economy. Not only have the research costs incurred by industry been recouped from the public [63], but the resulting evidence base is neither robust nor reliable. Moreover, as the patients end up paying for the treatments (either via taxation, insurance policies or out of pocket), the least-biased method for evaluating treatments would seem to be in their interest. Certainly, what we have written here suggests that patients would be saving money in the long run if trials were independent.
But hidden funding from the biggest polluters pays for most of the climate change denial literature, and that's even less trustworthy. One of the big things climate change deniers want is to eliminate the kind of independent research that is proving so valuable in pharmaceuticals.
