Making statistics intuitive
A Latin square is an experimental design that tests multiple treatments while controlling for two sources of unwanted variation, known as nuisance variables. These nuisance variables are factors that you are not studying directly but could affect the outcome of your experiment if left uncontrolled. [Read more…] about Latin Square Design in Experiments Explained
A within-subjects design is an experimental design where each participant experiences all treatment conditions in the experiment. The analysis compares how the same person performs under different conditions. This experimental design is also called a dependent group or repeated measures design. [Read more…] about Within Subjects Design in Experiments Explained
Observer bias occurs when a researcher’s expectations, opinions, or past experiences influence what they notice or record in a study. It’s also known as observation bias. [Read more…] about Observer Bias: Definition, Examples & Minimizing
A between-subjects design is a type of experiment that tests different treatment conditions on separate groups of people. After the experiment, researchers compare group outcomes to determine whether they differ. Statisticians also refer to this method as a between-group or independent measures design. [Read more…] about Between Subjects Design in Experiments Explained
Demand characteristics in psychology research are clues about a study’s research objectives. These clues give participants an idea of what the researchers hope to find and can cause them to change how they act or answer. Demand characteristics are only a concern in research involving human subjects. Hence, it’s a particularly big problem in psychology. It is a form of Response Bias. [Read more…] about Demand Characteristics in Psychology Studies
A randomized block design (RBD) is a prospective experimental design that helps reduce uncontrolled variability that could obscure or distort meaningful treatment effects. Typically, these designs control for nuisance factors, which are variables that can affect the outcome, but they are not the researcher’s primary interest. When experimenters know about specific nuisance factors, they can use blocking to minimize their impact. An RBD helps manage nuisance variability by grouping similar subjects into blocks before randomizing treatments within each block. [Read more…] about Randomized Block Design in Experiments Explained
A factorial design is an experimental design that simultaneously assesses more than one factor. By evaluating multiple factors at the same time, this design uncovers not only individual effects but also how factors interact. With this technique, each experimental run involves a random combination of factor values in a structured setting. [Read more…] about Factorial Design Explained: Testing Multiple Factors
Social desirability bias is the tendency for research participants to answer questions in a way that portrays them in a favorable light rather than providing completely honest responses. Typically, this bias occurs when participants answer questions to look better in the eyes of the researchers performing the study. It is a form of response bias, primarily affecting studies that use surveys and structured interviews to obtain self-reported information from the participants. However, it can occur in any study where the participants know researchers are watching. This bias reduces a study’s validity because the participants concealing their genuine opinions and behaviors. [Read more…] about Social Desirability Bias: Definition & Examples
Response bias occurs in studies when participants tend to provide inaccurate answers to questions. Societal norms and psychological factors can cause participants to systematically provide false responses. This research bias primarily affects studies that use surveys and structured interviews to obtain self-reported information from the participants. This bias reduces a study’s validity because the participants are concealing their true opinions and behaviors. [Read more…] about Response Bias: Definition & Examples
A double-blind study is an experiment where the researchers and subjects don’t know who has been assigned to the treatment or control group. This experimental design deliberately hides treatment statuses from subjects and researchers to minimize biases that can occur when they know this information. [Read more…] about Double Blind Study Overview & Example
A controlled experiment assesses causal relationships between treatments and outcomes by systematically manipulating the treatments and controlling other variables. The goal is to determine whether the treatment causes changes in the outcomes. [Read more…] about Controlled Experiment: Definition & Examples
The Hawthorne effect occurs when experimental participants change their behavior because they know researchers are watching them. Typically, this effect refers to cases where subjects improve their performance levels. However, these are short-term improvements that vanish when the observation stops. Consequently, the study results are deceptive because they do not reflect a natural response to the experimental factors. [Read more…] about Hawthorne Effect: Definition & Examples
Naturalistic observation is a research method in psychology and other fields where investigators watch subjects performing natural behaviors in real-world settings. These studies don’t manipulate variables to see how that affects the outcomes. Instead, the focus is on recording normal behaviors in ordinary settings. Typically, the goal is to make observations while minimizing the effect of the researcher’s presence. These studies are also known as field studies. [Read more…] about Naturalistic Observation: Definition & Examples
Self selection bias can occur when individuals choose to participate in a study, survey, or experiment. The bias exists when volunteers have different characteristics than those who do not participate. It is a form of sampling bias stemming from using a nonprobability sampling method, such as volunteer or convenience sampling. [Read more…] about Self Selection Bias Overview & Examples
Attrition bias in research occurs when study participants who drop out have characteristics that differ significantly from those who remain. This selective dropout can lead to skewed results and misinterpretations if the researchers don’t adequately address it. This threat is higher for longitudinal studies and those with relatively high attrition rates. [Read more…] about Attrition Bias: Definition & Examples
A quasi experimental design is a method for identifying causal relationships that does not randomly assign participants to the experimental groups. Instead, researchers use a non-random process. For example, they might use an eligibility cutoff score or preexisting groups to determine who receives the treatment. [Read more…] about Quasi Experimental Design Overview & Examples
A case study is an in-depth investigation of a single person, group, event, or community. This research method involves intensively analyzing a subject to understand its complexity and context. The richness of a case study comes from its ability to capture detailed, qualitative data that can offer insights into a process or subject matter that other research methods might miss. Case reports are near the bottom of the level of evidence ranking, offering descriptive insights from individual or small patient series. [Read more…] about What is a Case Study? Definition & Examples
A correlational study is an experimental design that evaluates only the correlation between variables. The researchers record measurements but do not control or manipulate the variables. Correlational research is a form of observational study. [Read more…] about Correlational Study Overview & Examples
A cross-sectional study is an experimental design that analyzes data from a representative sample at a specific point in time. Researchers usually evaluate multiple attributes at once when using this design. Unlike longitudinal studies, these studies don’t track changes over time. [Read more…] about Cross Sectional Study: Overview, Examples & Benefits
A longitudinal study is an experimental design that takes repeated measurements of the same subjects over time. These studies can span years or even decades. Unlike cross-sectional studies, which analyze data at a single point, longitudinal studies track changes and developments, producing a more dynamic assessment. [Read more…] about Longitudinal Study: Overview, Examples & Benefits