: Levels of Measurement and Concepts of Validity. Quantitative in Public Health, - Research Paper Example

LEVELS OF MEASUREMENT AND CONCEPTS OF VALIDITY Answer the following questions Differences between the levels of measurement (type of measurement scale-nominal, ordinal, interval, or ratio- ). Providing an example of data that can be transformed from one level of measurement to another and another example of data that cannot be transformed. Measurement is the process of differentiating persons or things through testing, interviewing, observation, or other methods, and results in ratings, assignment of numbers, labels to persons, or measuring things (Goodwin & Goodwin, 1996).

Data obtained from measurement are classified by using numbers at different different precision or levels; the four levels in precise ascending order are: The nominal, ordinal, interval and ratio. In the nominal, numbers are used for the purpose of classifying data, words or letters would be congruently appropriate. For example, data or answers given to variables such as employment status (classified as 1); occupation (classified as 2) or place of residence (classified as 3). Usually, numbers are preferred since text takes up more space and longer to type out.

In ordinal scales, values assigned to measurements can be ordered, (for example, the shoe size) and the numbers of an ordinal scale present an ordered relationship between the numbered items. Interval scale on the other hand, has measurements that are not only classified but also ordered, therefore, it consist properties of the two previous scales, but there are equal distances between each interval on the scale from the low end until the high end (example: Temperature scale of 96o and 98oC is the same as between 100o and 102 oC.

Ratio scale have similar properties as interval scales as it represents quantity and has equality of units; but this scale has an absolute zero and no number exist below the zero; the distance between the points on the scale comprises the same distance between them, at the same time, these numbers on the scale are being ranked based on size; examples length, weight, speed, numbers of people and exam marks (Ucel collective, 2004). > Example of data that can be transformed from one level of measurement to another: Measuring the Annual Family Income using Ordinal Scale: 49,001 USD and above 17,001- 33,000 USD Below 1,000 USD 33,001 – 49,000 USD 1,001 - 17,000 USD Measuring Annual Family Income using Nominal Scale Please indicate your annual family income in USD: ______________ > Example of data that cannot be transformed to other level of measurement: nominal-level variables cannot be transformed into ordinal-level variables such as country of origin, place of birth, or gender because there is no information about the rank, degree or level to begin with.

The ordinal-level variables are likewise cannot be transform into ratio-level variables if the precise quantities are not determined to begin with (Rubin, 2009; p 26-27). 2. Compare the concept of validity for design to the concept of validity for measurement. There are several basic and advance designs that researchers can use. Validity in research design generally mean that process involved in carrying out of the research is accurate, objective, and are not influenced by internal and external factors (Royse, 2008; p 1220.

Meanwhile, validity of measurement points out the degree to which the data or scores from an instrument or test, “measures what it is supposed to measure”; thus, referring directly to the soundness of score interpretation; and is the most essential consideration in measurement (Thomas, Nelson & Silvverman, 2010; p 193). 3. What is the relationship between reliability and validity? Validity and reliability are two related, however, different concepts. Validity questions the correctitude of the measure in producing or generating the results.

It could be categorized into either internal validity or external validity; while reliability scrutinizes whether the same measure will come up or produce the same results. Reliability is the consistency, as well as, repeatability of a measure (Yuen, Terao & Schmidt, 2009) REFERENCES Goodwin, W.L. & Goodwin, L. D. (1996) Understanding quantitative research in early childhood education. Teachers College Press, New York, NY 10027, 73-79. Royse, D. D. (2008) Research methods in social work .Thomas Learning Inc.

, CA, USA, 135. Rubin, A. (2010) Statistics for evidence-based practice and evaluation. ( 2nd ed.) Brooks/Cole Cengage Learning Belmont CA 94002-3098, 26-28. Thomas, J.R., Nelson, J.K. & Silverman, S.J. (2010) Research methods in physical activity (6th ed.) Champaign, IL, USA., 193. Yuen, F.K., Terao K. L., & Schmidt, A. M. (2009) Effective grant writing and program evaluation for human service professionals. Jogn Wiley & Sons, Inc., Hoboken, New Jersey.