A megastudy or mega-study is a research study in which a large number of different treatments or interventions are tested at the same time, on the same sample or similar samples, using a common outcome measure, and using the same experimental protocol. [1] [2] [3]
This research design ensures the outcomes across interventions are comparable. Additionally, due to generous inclusion of various interventions in the study, megastudies may be less prone to publication bias, where the interventions expected to be effective are more likely to be studied and the interventions found to be ineffective are underreported due to the file-drawer problem. [4]
The megastudy technique can be combined with the many-labs approach, so that teams of researchers from across the planet conduct the same experiment locally. [3] [7]
Meta-analysis is the statistical combination of the results of multiple studies addressing a similar research question. An important part of this method involves computing an effect size across all of the studies, this involves extracting effect sizes and variance measures from various studies. Meta-analyses are integral in supporting research grant proposals, shaping treatment guidelines, and influencing health policies. They are also pivotal in summarizing existing research to guide future studies, thereby cementing their role as a fundamental methodology in metascience. Meta-analyses are often, but not always, important components of a systematic review procedure. For instance, a meta-analysis may be conducted on several clinical trials of a medical treatment, in an effort to obtain a better understanding of how well the treatment works.
Epidemiology is the study and analysis of the distribution, patterns and determinants of health and disease conditions in a defined population.
Behavioral economics is the study of the psychological, cognitive, emotional, cultural and social factors involved in the decisions of individuals or institutions, and how these decisions deviate from those implied by classical economic theory.
Selection bias is the bias introduced by the selection of individuals, groups, or data for analysis in such a way that proper randomization is not achieved, thereby failing to ensure that the sample obtained is representative of the population intended to be analyzed. It is sometimes referred to as the selection effect. The phrase "selection bias" most often refers to the distortion of a statistical analysis, resulting from the method of collecting samples. If the selection bias is not taken into account, then some conclusions of the study may be false.
In the human brain, the anterior cingulate cortex (ACC) is the frontal part of the cingulate cortex that resembles a "collar" surrounding the frontal part of the corpus callosum. It consists of Brodmann areas 24, 32, and 33.
In statistics, an effect size is a value measuring the strength of the relationship between two variables in a population, or a sample-based estimate of that quantity. It can refer to the value of a statistic calculated from a sample of data, the value of a parameter for a hypothetical population, or to the equation that operationalizes how statistics or parameters lead to the effect size value. Examples of effect sizes include the correlation between two variables, the regression coefficient in a regression, the mean difference, or the risk of a particular event happening. Effect sizes complement statistical hypothesis testing, and play an important role in power analyses, sample size planning, and in meta-analyses. The cluster of data-analysis methods concerning effect sizes is referred to as estimation statistics.
In published academic research, publication bias occurs when the outcome of an experiment or research study biases the decision to publish or otherwise distribute it. Publishing only results that show a significant finding disturbs the balance of findings in favor of positive results. The study of publication bias is an important topic in metascience.
Loss aversion is a psychological and economic concept which refers to how outcomes are interpreted as gains and losses where losses are subject to more sensitivity in people's responses compared to equivalent gains acquired. Kahneman and Tversky (1992) have suggested that losses can be twice as powerful, psychologically, as gains. When defined in terms of the utility function shape as in the cumulative prospect theory (CPT), losses have a steeper utility than gains, thus being more "painful" than the satisfaction from a comparable gain as shown in Figure 1. Loss aversion was first proposed by Amos Tversky and Daniel Kahneman as an important framework for prospect theory – an analysis of decision under risk.
In-group favoritism, sometimes known as in-group–out-group bias, in-group bias, intergroup bias, or in-group preference, is a pattern of favoring members of one's in-group over out-group members. This can be expressed in evaluation of others, in allocation of resources, and in many other ways.
Field experiments are experiments carried out outside of laboratory settings.
In cognitive science and neuropsychology, executive functions are a set of cognitive processes that are necessary for the cognitive control of behavior: selecting and successfully monitoring behaviors that facilitate the attainment of chosen goals. Executive functions include basic cognitive processes such as attentional control, cognitive inhibition, inhibitory control, working memory, and cognitive flexibility. Higher-order executive functions require the simultaneous use of multiple basic executive functions and include planning and fluid intelligence.
Attentional bias refers to how a person's perception is affected by selective factors in their attention. Attentional biases may explain an individual's failure to consider alternative possibilities when occupied with an existing train of thought. For example, cigarette smokers have been shown to possess an attentional bias for smoking-related cues around them, due to their brain's altered reward sensitivity. Attentional bias has also been associated with clinically relevant symptoms such as anxiety and depression.
Vaccine efficacy or vaccine effectiveness is the percentage reduction of disease cases in a vaccinated group of people compared to an unvaccinated group. For example, a vaccine efficacy or effectiveness of 80% indicates an 80% decrease in the number of disease cases among a group of vaccinated people compared to a group in which nobody was vaccinated. When a study is carried out using the most favorable, ideal or perfectly controlled conditions, such as those in a clinical trial, the term vaccine efficacy is used. On the other hand, when a study is carried out to show how well a vaccine works when they are used in a bigger, typical population under less-than-perfectly controlled conditions, the term vaccine effectiveness is used.
Impact evaluation assesses the changes that can be attributed to a particular intervention, such as a project, program or policy, both the intended ones, as well as ideally the unintended ones. In contrast to outcome monitoring, which examines whether targets have been achieved, impact evaluation is structured to answer the question: how would outcomes such as participants' well-being have changed if the intervention had not been undertaken? This involves counterfactual analysis, that is, "a comparison between what actually happened and what would have happened in the absence of the intervention." Impact evaluations seek to answer cause-and-effect questions. In other words, they look for the changes in outcome that are directly attributable to a program.
Nudge theory is a concept in behavioral economics, decision making, behavioral policy, social psychology, consumer behavior, and related behavioral sciences that proposes adaptive designs of the decision environment as ways to influence the behavior and decision-making of groups or individuals. Nudging contrasts with other ways to achieve compliance, such as education, legislation or enforcement.
A neurological look at race is multifaceted. The cross-race effect has been neurologically explained by there being differences in brain processing while viewing same-race and other-race faces. There is a debate over the cause of the cross-race effect.
Neurosexism is an alleged bias in the neuroscience of sex differences towards reinforcing harmful gender stereotypes. The term was coined by feminist scholar Cordelia Fine in a 2008 article and popularised by her 2010 book Delusions of Gender. The concept is now widely used by critics of the neuroscience of sex differences in neuroscience, neuroethics and philosophy.
Katherine L. Milkman is an American economist who is the James G. Dinan endowed Professor at The Wharton School of the University of Pennsylvania. She is the President of the Society for Judgment and Decision Making.
Modupe Nyikoale Akinola is an American organizational scholar and social psychologist who examines the science of stress, creativity, and how to maximize human potential in diverse organizations. She is currently the Barbara and David Zalaznick Professor of Business at Columbia Business School, where she is the Director of the Sanford C. Bernstein & Co. Center for Leadership and Ethics.
Michael Muthukrishna is an associate professor of economic psychology at the London School of Economics and Political Science (LSE), in England. He is an affiliate of the Developmental Economics Group at the LSE's STICERD, technical director of UBC's Database of Religious History, and CIFAR's Azrieli Global Scholar in the Boundaries, Membership and Belonging programme. His main area of interest is the application of research in cultural evolution to public policy.