Final answer:
In the CELF-5 assessment, raw scores are converted to scaled scores and then to standard scores, which are on a ratio scale and provide a comparison to the normative sample.
Step-by-step explanation:
When scoring the CELF-5, you use the table to convert a raw score into a scaled score and a standard score. The CELF-5, or the Clinical Evaluation of Language Fundamentals, is an assessment tool designed to evaluate the language skills of children aged 5 to 21 years. The instrument measures a student's performance in aspects such as semantics, morphology, syntax, and language memory. Upon administering the test and obtaining raw scores, these are then converted using standardized tables provided in the test's manual. The conversion process involves finding the corresponding scaled score for the raw score and then further converting the scaled score into a standard score, which reflects where the student stands in comparison to the normative sample.
Standard scores are part of a ratio scale, which means that in addition to having equal intervals between points, this scale also has an absolute zero point, allowing for the calculation of ratios. This is different from interval scales, which do not have a true zero, and therefore, do not allow for the calculation of ratios. In the field of assessment and measurement, understanding the different levels of measurement—nominal, ordinal, interval, and ratio—is crucial to selecting the right statistical tools for analysis and correctly interpreting the results.
Ultimately, the significance of converting raw scores to standard scores is to provide a meaningful metric that can be used to compare a student's performance across different tests or with their peers, taking into account age and grade-level expectations.