Do consumer beliefs and labeling create measurement bias in studies?
Yes, consumer perception studies are particularly vulnerable to measurement bias because people's pre-existing attitudes can confound their ratings. In a 2023 Dutch online questionnaire study with 120 consumers, researchers found that participants consistently perceived plant-based meat alternatives as healthier than real meat, even though the actual nutritional data showed that alternatives often contained less protein and more salt [4]. This mismatch between perception and reality means that any study relying on self-reported healthiness ratings is measuring biased beliefs, not objective nutritional value.
Labeling itself is a major source of bias. A 2022 study using two online experiments found that when a plant-based product was labeled 'vegan,' consumers rated it as less tasty and less healthy, and their willingness to buy dropped significantly [3]. Importantly, this effect was moderated by the consumers' attitudes toward meat-eating and veganism—meaning that the same product got different ratings depending on who was tasting it. This is a classic confounding variable: the label triggers an emotional or ideological response that distorts the measurement of the product's actual appeal.
Are nutritional comparison studies less biased?
Nutritional comparison studies that analyze actual chemical composition (like fatty acid profiles) are less prone to measurement bias because they rely on objective lab tests rather than subjective ratings. For example, a 2026 study in Hungary analyzed the fatty acid composition of six plant-based and four beef hamburger patties using gas chromatography—a precise lab method [1]. They found significant differences in fat content and fatty acid profiles, with plant-based alternatives generally having lower saturated fat and higher polyunsaturated fat, except for those containing coconut oil. This kind of direct measurement avoids the perception biases seen in consumer surveys.
However, even these objective studies face confounding because plant-based products are not a uniform category. The same Hungarian study noted that one plant-based product (containing coconut oil) had a very different fatty acid profile from the others, which could confound comparisons if researchers lump all plant-based products together [1]. Similarly, a 2022 Norwegian study comparing 102 meat substitutes and 173 dairy substitutes found that while substitutes generally had lower saturated fat and higher fiber, they also had less protein and more salt—but the variation within the substitute category was large [5]. So, the bias here is not measurement error but confounding by ingredient variability: the 'plant-based' label hides a wide range of nutritional realities.
Do economic studies on willingness to pay suffer from confounding?
Yes, economic studies that measure willingness to pay for plant-based meat substitutes are highly susceptible to confounding from individual differences like time preference and gender. A 2022 randomized control study using an experimental auction found that participants' willingness to pay a premium for sustainably produced beef or plant-based meat substitutes was influenced by whether they were 'present-biased' or 'future-biased' in their time preferences [2]. For example, present-biased female participants who received an information nudge were willing to pay a significantly lower premium for sustainably produced beef compared to the control group, while future-biased participants were more likely to pay a premium for the plant-based substitute. This means that any study measuring willingness to pay without accounting for participants' time preferences is likely to have confounding bias—the effect of the treatment (information nudge) is mixed up with the effect of the participant's personality.
Furthermore, the same study found that the effect of information nudging varied with participant characteristics like gender and time preference, which means that simple averages can be misleading. If a study reports that 'consumers are willing to pay X% more for plant-based meat,' that number may be confounded by the mix of present-biased and future-biased people in the sample. This is a clear example of confounding bias in economic experiments.
About These Sources
This answer is built on 5 peer-reviewed studies — published from 2022 to 2026, 1 from 2024 or later, 4 in Q1 journals, collectively cited 193 times — selected as the most relevant from 5 studies that passed quality screening, drawn from 55 papers retrieved from a database of over 500 million.
Sources used in this answer
Fatty acid composition of ground-beef products and their plant-based meat substitutes available in Hungary
A 2026 Hungarian study comparing fatty acid profiles of plant-based and beef patties using gas chromatography found that plant-based alternatives generally had lower saturated fat and higher polyunsaturated fat, but one product with coconut oil deviated significantly, highlighting ingredient variability as a confound.
Consumer willingness to pay for environmentally sustainable meat and a plant‐based meat substitute
A 2022 randomized control auction study found that participants' time preference (present-biased vs. future-biased) confounded their willingness to pay for sustainably produced beef and plant-based meat substitutes, with effects varying by gender.
Would you buy vegan meatballs? The policy issues around vegan and meat-sounding labelling of plant-based meat alternatives
A 2022 two-experiment study found that 'vegan' labeling on plant-based foods negatively biased consumers' perceptions of tastiness and healthiness, and these effects were moderated by attitudes toward meat-eating and veganism.
Fake meat or meat with benefits? How Dutch consumers perceive health and nutritional value of plant-based meat alternatives
A 2023 Dutch online questionnaire with 120 consumers found that participants overestimated the protein content of plant-based meat alternatives and perceived them as healthier than meat, despite actual nutritional data showing lower protein and higher salt.
Plant-based meat and dairy substitutes on the Norwegian market: comparing macronutrient content in substitutes with equivalent meat and dairy products
A 2022 Norwegian market comparison of 102 meat substitutes and 173 dairy substitutes found that while substitutes had lower saturated fat and higher fiber, they also had less protein and more salt, with large variability within the substitute category.