Definitions

Blinded study: when the participant is not aware if they are receiving treatment or a placebo (Blinded Clinical Trial, n.d.).

Covariance: "the expected value of variations of two variables from their expected values. More simply, covariance measures how much variables change together" (Kim, 2018, para. 2).

Crossover designs: "two or more treatments (e.g., drugs, procedures) are provided to subjects at different time periods, and the sequence of treatments is randomized for each subject" (Lim & In, 2021, para. 2).

Double-blinded study: where the participant and the practitioner are both unaware if the participant is receiving the treatment or the placebo (Blinded Clinical Trial, n.d.)

Extended repeated measures: Treatments that require a follow up to assess the effect a design “can include subsequent tests at more than one time” (Meltzoff & Cooper, 2018, p. 112)  

Implicit cultural assumptions: "whether they apply to individualistic or collective cultures" (Bhattacherjee, 2012, p. 28)  

Maturation: The process of a population developing naturally over a period of time (Meltzoff & Cooper, 2018) 

Multiple independent variables (i.e. A1 x B1 and A1 x C1): Using two treatment groups and not using a control group OR using “more than one measurement so time is another controlled variable” (Meltzoff & Cooper, 2018, p. 113) 

Probabilistic equivalence: when randomization is used, "we know perfectly the odds that we will find a difference between" the control and testing group, but the "means" of the groups with be close to each other ( Trochim, 2006)

Randomization: referring to both random selection, "how you draw the sample of people for your study from a population" and random assignment, "how you assign the sample that you draw to different groups or treatments in your study" (Trochim, 2006). 

Randomized controlled trial (RCT): golden standard for experiments. Trials in which the participants are randomly assigned to either the treatment or placebo limb, and then compared to one another to assess if the treatment is effective. This method decreases biases (NICE, n.d.).

Saturation: In regards to research, saturation means reaching a point of assumed complete understanding of a topic of study (as you can not simply study the entire world, now can you?; Meltzoff & Cooper, 2018) 

Solomon Four Group method: Creating four sample groups where two received the treatment and two groups are control groups AND one control and one treatment group complete the pretest but the other two groups do not (Trochim, 2006).  

Spatial assumptions: " whether they apply to certain localities but not to others"   (Bhattacherjee, 2012, p. 28)  

Stratification: sorting participants, data or objects into distinct groups or categories. Can be done  (American Society for Quality, 2023)

Switching replication designs: a strong experimental design where both sample groups receive the treatment as they switch control group and treatment group and repeat the study after the first completion (Trochim, 2006). 

Temporal assumptions: "whether they apply to early stages or later stages of human behavior" (Bhattacherjee, 2012, p. 28)