PS 522: Behavioral Measures and Interpretation of Data Lisa R. Jackson, Ph.D.

 The process of applying quantitative labels to observed properties of events using a standard set of rules

 How scientists operationalize empiricism ◦ Without measurement, science is guesswork and opinion  Applied behavior analysts measure behavior to answer questions ◦ Basis for talking about behavior ◦ Determining increases, decreases ◦ To test the usefulness of interventions

 To evaluate effects of intervention ◦ Before and after treatment ◦ During treatment  To guide decision making  To prevent mistakes ◦ Continue ineffective treatment ◦ Discontinue effective treatment

 In general, measurements can be classified into four different types of scales:  Nominal  Ordinal  Interval  Ratio  Different scales allow you to use different data and analyze it differently  You want to know how you want to analyze before you collect data, so you know what to collect, know what questions to ask

 Nominal scales put data into categories:  Male/female, yes/no responses, mood disorders, anxiety disorders, behaviors  You can calculate the mode, but not the mean or median  Ex: You can’t average male/female

 Ordinal scales rank data in order  You can determine the order, but not the difference between data  You can ask how often a child kicks another child: always, frequently, infrequently, never, but you can’t tell how many more kicks frequently is than infrequently  You can also ask how severe a disorder is, with 1 being mild and 7 being severe ◦ But you can’t tell if a 2 is 3x as severe as 1 or if 5 is 8x as severe as 2  With ordinal data, you can find a mean or percentile

 Interval scales put data into order at specific intervals  The distance between 1 and 25 is the same as the distance between 72 and 96  Likert scales are an example of an interval scale, where the difference between 3 and 4 is the same as the difference between 6 and 7  With interval data, you can calculate a mean, median, standard dev, correlation, regression, ANOVA

 Ratios are a measure of a value in relation to a constant ◦ Time is an example: minutes are a unit of an hour, days are a unit of a year, etc ◦ A percentage is a ratio: 24 out of 30 on a test = 80%  Ratio scales have an absolute zero, as compared to an interval scale where 0 is arbitrary  With ratios, you can calculate mean, median, mode, standard dev, correlation, regression, ANOVA, ANCOVA, logarithms

 Dimensions are distinct features that can be measured  Used to detect and compare changes in behavior and environment  Looks at levels of behaviors, changes in behaviors, impact of the introduction or withdrawal of variable and stability of changes  Three fundamental properties: ◦ Repeatability or countability: behavior can be counted ◦ Temporal extent: duration, measured in time, how long it lasts ◦ Temporal locus: when behavior occurs relative to other events  Ex: latency (how long after an event)  Inter-response time, time between 2 events

 A tally of the number of occurrences of a behavior ◦ The number of mat problems a child gets correct  Reported as a standard number  Count may not always provide much useful information, though  If Katie got 5, 10 and 15 answers correct over 3 days, that might seem like improvement until you realize that the counts covered 5 min, 20 min and 2 hours  Therefore, the time period must always be designated

 Rate/Frequency ◦ Ratio of count per observation period  More meaningful than count alone ◦ Previous example: Katie got 1 problem correct/min,.5 problem correct/min, and.125 problem correct/min, so you can see she’s not improving  Include counting time for reference  Rate of correct and incorrect responses helpful in skill development  Reported as number per standard unit of time

 Duration ◦ The amount of time a behavior occurs; how long someone engages in the target behavior  Can be used for behaviors that have a high rate of frequency (rocking, hand flapping, etc)  Duration of session: ◦ Cumulative time within an observation period, ex: during 30 min free play ◦ Amount of time person spends in an activity, no minimum or maximum time; time spent in the senior center  Duration of each occurrence: how long each event lasts ◦ Bobby was out of his seat for 3, 7, 2, 4 and 8 min on Thursday  Count and duration measures provide different pictures of same behavior

 Response latency ◦ Measure of elapsed time between onset of stimulus and initiation of response  How long does the student delay before complying with directions?  How long does the teen wait before retaliating against others?  Typically reported as mean, median, and range

 Interresponse time (IRT) ◦ The amount of time that elapses between two consecutive instances of a response  How long between outbursts?  Shorter IRTS are associated with higher rates of response  Longer IRTS are associated with lower rates of response  Very useful when trying to reduce rates of responding using DRL  Typically reported as mean, median, and range per observation period

 Percentage ◦ A ratio formed by combining the same dimensional qualities (number/number, duration/duration ◦ Expresses proportional quantity  Proportion of correct to incorrect  Proportion of observation intervals when behavior occurred  Can’t be used for all measures, but is easily understandable

 Trials-to-criterion ◦ Number of response opportunities needed to achieve a predetermined level of performance  How many trials required to tie a shoe correctly  Often reported as the “cost” of a treatment or instructional method  Often used to compare the efficacy of different treatments or instructional methods  Can assess changes in competence ◦ Fewer trials needed to learn color red than blue than yellow = increasing skill in learning colors

 Topography ◦ The physical form or shape of a behavior  Measurable dimension  Malleable by consequences  Important where form, style are valued ◦ Painting, sculpting, dancing, gymnastics, handwriting  Specific topographies produce different outcomes ◦ Sitting up straight, looking at teacher vs. slouching with head on desk  Not a fundamental quality of behavior

 Magnitude ◦ The force or intensity with which a response is emitted  Important parameter for some responses ◦ Voice volume: too low or too high ◦ Pressing a pencil too hard or not hard enough  Not a fundamental quality of behavior

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