Homework answers / question archive / each note should be composed of four parts: Notes Description of everything observed or that can be remembered Analysis Reflection ACTIVITY INSTRUCTIONS For this assignment, write 2-3 field note entries on defining and measuring variables in your own field: The different measurement scales (ordinal, nominal, ratio, and interval) Be sure to operationally define the dependent variable being measured with the scale

each note should be composed of four parts: Notes Description of everything observed or that can be remembered Analysis Reflection ACTIVITY INSTRUCTIONS For this assignment, write 2-3 field note entries on defining and measuring variables in your own field: The different measurement scales (ordinal, nominal, ratio, and interval) Be sure to operationally define the dependent variable being measured with the scale

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each note should be composed of four parts: Notes Description of everything observed or that can be remembered Analysis Reflection ACTIVITY INSTRUCTIONS For this assignment, write 2-3 field note entries on defining and measuring variables in your own field: The different measurement scales (ordinal, nominal, ratio, and interval) Be sure to operationally define the dependent variable being measured with the scale. Reliability and validity.

PSY 305 M2.5 Define and Measure Read Salkind text, pages 61-66, 105-107, 108-112, 113-121 Operational Definition of a Variable When conducting research, it is important to define your variables. An “operational definition of a variable in terms of the operations (activities) a researcher uses to measure or manipulate” (Jackson, 57). What does that mean? Video Operational Definitions Time: 3:08 Closed captioned Once you operationally define your variable, you can start planning out how to measure it. Measurement is the process of assigning numbers to objects based on a set of rules. This is where your operational definition comes in handy, since this should clearly state your rules for measurement. As mentioned in your reading, there are four different scales of measurement. Here is a quick knowledge check of your understanding of the four different scales. Identify the scale of measurement in the list below. Video Types of Scales of Measurement Explained Time: 4:01 Closed captioned Which scale of measurement corresponds to each item (nominal, ratio, interval, ordinal)? 1. Baseball uniform numbers 2. Temperature in degrees Fahrenheit 3. Weight in pounds 4. Academic letter grade Now that you have an operational definition and you have identified the appropriate scale of measurement for your study, I bet you are wondering what the different types of measures are. There are four predominate types of measures, including (Jackson, 62-65): Self-Report Self-report measures are probably one of the most common measures. These include questionnaires or interviews that measure individuals’ perceptions (i.e., how they think or feel) or how they report that they act. There are some factors to keep in mind when using self-report data, including: 1. Biased data, which could be the result of how the questions were phrased or the options presented. 2. Are participants telling the truth or are they providing answers that they think the researcher wants? Tests Tests are another measure that are fairly common. Tests are instruments designed to assess individual differences (e.g., aptitude tests and personality tests). When using tests, you should be aware of the following weaknesses: • The reliability and validity of the measure (we will get into specifics of reliability and validity later on in this module). • Are participants telling the truth or are they providing answers that they think will give them a specific outcome (e.g., on a personality test)? Behavioral Measures Behavioral measures are taken through careful observation, and the researcher must record the behavior. This involves classifying and counting behaviors. When using behavioral measures, you should be aware of: • The fact that people tend to react differently when they know they are being watched. • How a researcher classifies a behavior can be biased or the individuals conducting the observation may not be objective. Physical Measures Physical measures are direct measures of bodily activity. For example, the physical fitness tests done in school typically involve having students complete as many sit-ups as possible in one minute, running one mile, long jump, etc. As adults, we may think of an EKG or electrocardiogram measuring the electrical activity of an individual’s heartbeat. Somethings to keep in mind when using physical measures include: • Is the individual trained at using the equipment and reading the results? For example, were the electrode patches for the EKG attached correctly? • Do the instruments or equipment periodically need to be recalibrated? Are they maintained appropriately? If not, this could impact reliability and validity. When it comes to measuring your variable(s), you must always account for error. There are two different types of errors, trait and method errors. As stated in the Salkind text on page 108, a trait error is one associated with the individual and as a researcher, you have little to no control over this type of error. For example, if one of the participants in your study is extremely anxious, which can influence their responses and behaviors. As the researcher, you should do what you can to make the participant less anxious, unless of course you are studying anxiety and this is the state you want your participants in, maybe utilizing comfortable chairs or calming music. Method error is typically something that the researcher has control over. For example, if the survey you are administering is in English, but your target sample includes individuals whose first language is not English, then you run the risk of having those individuals misinterpret the survey instructions and items. This misinterpretation will influence the results. As a researcher, it is important to control for as many errors as possible, since errors are threats to the reliability and validity of your study. Reliability and Validity Why are reliability and validity important??? Reliability and validity are important because you want to make sure that your measurement instrument is measuring what you intended to measure and is measuring your variable the exact same way each time. By using valid and reliable measures, you are decreasing your chance for error.?? Your Salkind text covered reliability and validity in detail. To make sure you have a proper understanding of the two concepts, please complete the following Knowledge Check:

1. In this scenario, a researcher measures a behavior in a research sample and then re-measures the same behavior with the same participants a few weeks later. If the data provided by each person is very similar on both occasions, this measurement can be called: a. Generalizable b. Reliable c. Valid d. Parallel

2. If a measurement of anxiety on a standardized inventory correlates with a behavioral measure of anxiety, the measurement has established what type of validity?

a. Test-retest

b. Content

c. Concurrent

d. Parallel forms

3. If raters agree 30 times out of 90, the inter-rater reliability is:

a. 0.33

b. 3

c. 0.67

d. Cannot be determined

4. Which of the following is true?

a. Inter-Rater reliability is determined by examining the relationship between scores for two different forms at the same time.

b. Parallel forms reliability is determined by examining the relationship between scores on the same test administered at two different points in time.

c. Internal consistency reliability is determined by examining the relationship individual item scores and the total test score.

d. Test-Retest reliability is determined by the number of times rater agree on a score divided by the number of possible agreements. For the following items, indicate whether the statement is true or false.

5. A test cannot be valid without being reliable.

6. Construct validity is the extent to which a measuring instrument accurately predicts behavior or ability in a given area. Criterion validity is a measure of the consistency of a measuring instrument.

7. Criterion validity is a measure of the consistency of a measuring instrument.

8. Content validity is the extent to which a measuring instrument covers a representative sample of the domain of behaviors to be measured.

9. A _____ test compares the performance of one individual to the performance of other individuals. a. Criterion-referenced b. Parallel forms c. Predictive d. Norm-referenced

10. Test-retest reliability is assessed when: a. Two different forms of a measure are administered at the same time b. The same form is administered on two different occasions c. Different judges evaluate the same behavior or performance d. Two or more concepts are being assessed