To be held responsible for an action; being required to give an explanation for something; the obligation to bear the consequence for failure to perform as expected.

All behaviors are preceded by some event in the person's environment. The preceding event is called the antecedent.

ABA is the application of behavioral science to the analysis of behavior and is based on the approach to psychology founded by B. F. Skinner. ABA’s success has been due to the ability of the field to successfully utilize Skinner's procedures of operant conditioning, the modification of behavior brought about by arranging consequences that follow the occurrence of the behavior. In the applied setting. ABA’s greatest impact has been in addressing the education, social and communication needs of children with autism.

A form of qualitative descriptive research used to investigate individuals, a small group of participants, or a group as a whole. Data is obtained through the use of direct observations, interviews, tests, examinations of records, and/or collections of writing samples.

The relationship between cause and effect. When causality exists, there is predictability between the two events. It is presumed that the cause chronologically precedes the effect. The existence of a causal relationship suggests that, all things equal, if the cause occurs the effect will as well (or at least the probability of the effect occurring increases).

The fundamental purpose of a clearinghouse is to collect, evaluate, and distribute information to people who have interest in a specific field. This clearinghouse acts as a central access point to serve the needs of educators, parents, and policy makers who have an interest in evidenced-based educational research and practices.

Our environment controls our behavior. When a behavior occurs it is strengthened or weakened by the consequences that follow it. The consequences that increase the likelihood of a behavior occurring are referred to as reinforcers, i.e., positive or negative reinforcement. The consequences that decrease the likelihood of a behavior occurring are punishment or extinction.

The relationship between two events. The degree to which one phenomenon or random variable is associated with or can be predicted from another. Systematic patterns are frequently revealed through observing occurrences of correlated events. Because two events are correlated does not establish that one causes the other, or has anything to do with the other. A strong correlation, however, may act as an indicator for conducting additional research to determine causation.

Correlation is a common and useful statistic frequently referred to in educational research. A correlation is a single number describing the strength and degree of relationship between two variables. Correlation cannot be used to infer a causal relationship between the variables. Correlation may be an indicator of a causal relationship or it may only reflect a relationship in which no direct causal process exists.

Databased decision making is the selection of a course of action from among multiple alternatives based on objective and reliable facts. There exists a critical need for educators to make decisions based on verifiable facts and data, rather than on gut feel and experience. The reality is that educators find it increasingly difficult to access the information required to make accurate decisions and frequently are forced to make critical decisions based on faulty information or purely on opinion.

Descriptive research obtains information concerning phenomena and can describe, "what exists" with respect to variables or conditions in a situation. It describes the phenomena, compares similarities and difference among events to determine if certain factors or circumstances tend to be associated, determines the relationship between two or more variables, and/or determines changes that occur over time.

Direct instruction is a model for teaching that emphasizes well-developed and carefully planned lessons designed around small learning increments and clearly defined and prescribed teaching tasks. It is based on the theory that clear instruction, immediate feedback, and repetition can accelerate the fluency of skills. (Fluency is a combination of accuracy plus speed of the mastered skills).

 A method of instruction that consists of a series of systematic repeated lessons “trials” that are presented one after the other that builds toward the full acquisition of a skill. Each trial consists of an “antecedent” (see antecedent), a request or instruction for the student to perform a specific skill or behavior, the student’s demonstration of the requested skill, and an immediate specific consequence from the instructor based on the response from the student.

The effect size is a standardized measure of the effect of an intervention (treatment) on an outcome. The effect size represents the change (measured in standard deviations) in an average outcome that can be expected if that person is given the treatment. Because effect sizes are standardized, they can be compared across studies. Adapted from U.S. Department of Education, Institute of Education Science http://ies.ed.gov/ncee/wwc/help/glossary/ 

Effect size measures play an important role in meta-analysis studies that summarize findings from a specific area of research. In practical situations, effect sizes are helpful for making decisions, since a highly significant relationship may be uninteresting if its effect size is small.

The generally accepted benchmark for effect size comes from Jacob Cohen, a US statistician and psychologist.

Cohen (1988) hesitantly defined effect sizes as "small, d = .2," "medium, d = .5," and "large, d = .8", stating that "there is a certain risk in inherent in offering conventional operational definitions for those terms for use in power analysis in as diverse a field of inquiry as behavioral science." "The terms 'small,' 'medium,' and 'large' are relative, not only to each other, but to the area of behavioral science or even more particularly to the specific content and research method being employed in any given investigation. This risk is nevertheless accepted in the belief that more is to be gained than lost by supplying a common conventional frame of reference which is recommended for use only when no better basis for estimating the Effect Size index is available."

Adapted from Lee A. Becker 1998, 1999 - http://www.uccs.edu/~faculty/lbecker/es.htm

Sample Size: The importance of sample size when calculating effect size has recently become an issue of controversy with the publication of the What Works Clearinghouse (WWC) procedures for reviewing the quality of research studies. These guidelines require that only the highest rating be given to randomized controlled studies in which there are statistically significant effect sizes. Unfortunately, these guidelines do not take into account the impact small sample sizes can have on calculating effect sizes. Studies with small sample sizes have the potential to play a disproportional effect and thus produce inaccurate effect sizes when combined with other studies in a meta-analysis. This fact would indicate the need for developing methods for computing accurate effect sizes when employing studies of varying sizes.

Additional Information:
Stating the Meaning of Effect Size Measures in Plain English http://www.mclibrary.duke.edu/subject/ebm/stating_effect.pdf

The ability to implement an "efficacious" policy or practice.

A policy or practice successfully meets the intended results or "works" as evidenced by verifiable research.

The application of the scientific method to produce and implement the best policies and practices to achieve results.

The research method best designed to determine the causal relationship between two variables, the Independent Variable, the variable that is manipulated by the experimenter, and the Dependent Variable, the outcome variable or results of the experiment. A controlled experiment compares the results observed from an experimental sample against a control sample. The control sample is virtually identical to the experimental sample except for the one variable that is being investigated. The experiment first attempts to answer the question, did the experiment make the difference rather than other extraneous variables. Additionally the experiment attempts to answer the question, to what populations, settings, treatment variables, and/or measurement variables can the results of the experiment be generalized?