Update:  Iowa’s national percentile rank cut scores for accountability purposes are based on the 2000 national sample.  The Iowa Testing Program selected a new national sample for national percentile rank comparison purposes in 2011.  As a result, current national percentile ranks are not equivalent to prior years’ national percentile ranks.  That is, a 4th grade math performance that would have received a 50th percentile rank (proficient) when compared to the 2000 national sample only receives a 38th percentile rank (not proficient) when compared to the 2011 national sample.

The student’s performance is the same; only the relative standing within the sample has changed.  Thus, the Iowa Testing Program mapped the 2000 national percentile rank cut scores for proficiency reporting onto the Iowa Assessments’ standard score scale, establishing standard score scale cut scores that are equivalent to the 41st and 90th national percentile rank cut scores from 2000.  The standard score scales (available here) will now be used for proficiency reporting (equivalent to prior years’ proficiency reporting) instead of the national percentile ranks (no longer equivalent).

(From the Iowa Department of Education)

Proficiency Descriptors Used in Iowa

The Achievement Levels Report for the ITBS and ITED is provided to Iowa schools to help describe the level of performance of student groups and monitor the progress of groups over time. For each of the three main achievement levels—Low, Intermediate, and High—descriptors are included on the report to identify what the typical student in each level is able to do. For accountability purposes, the Iowa Department of Education has combined the Intermediate and High performance levels to define a single achievement level called “Proficient.” This document was prepared to explain how the descriptors for the “Proficient” level of performance were derived and how they should be interpreted.

The method for developing these descriptors was the same benchmarking approach that was used initially to create the descriptors for the Achievement Levels Report. (Details can be found in the leaflet, “Interpretive Guide for the Achievement Levels Report, 2003 Version,” which is available as a downloadable document from the Iowa Testing Programs website.) The operational definition for Proficient, as determined by the Iowa Department of Education (in consultation with the U.S. Department of Education), uses the national percentile rank scale from the Iowa Tests. Low performance is the range 1-40, Intermediate is 41-89, and High is 90-99. Consequently, the Proficient range is percentile ranks 41-99; 1-40 is regarded as Less-than-Proficient.

An achievement level descriptor tells what the typical student in a score range knows or is able to do relative to the content measured by the test. Because those who perform at a higher level within the range can probably do more and those who perform at a lower level within the range can do less, achievement level descriptors should not be used to describe what individual students can do. That is, descriptors are intended to show what group performance is like within a range on an achievement continuum. Individuals who are classified within the same achievement level are likely to vary from one another extensively, more so when the range encompassed by the achievement level is wide. For example, those within the range 41-99 should be expected to differ from one another much more than those within the range 76-99.

When used to label an achievement level, the term “Proficient” embodies a performance standard. It is a term that connotes sufficiency of performance– achievement that is regarded as “good enough.” Achievement level labels such as “Low”, “Intermediate”, and “High” are merely descriptive without conveying a judgment about sufficiency. However, the term Proficient describes and indicates that the level of performance is acceptable or minimally sufficient for some circumstance or purpose. In the current accountability context, Proficient and Less- than-Proficient are labels being used to describe the performance of groups that areat or above an acceptable standard or below that standard, respectively. That standard is determined by the test score user–the Iowa Department of Education in this case. In this accountability context, these descriptors should help schools interpret the concept of proficiency and convey the appropriate meaning in their public reporting of achievement data.

Grade 4

Proficient Performance in Reading Comprehension

Usually understands factual information and new words in context. Usually is able to make inferences and interpret either nonliteral language or information in new contexts. Often can determine a selection’s main idea and analyze its style and structure.

Grade 8

Usually is able to understand factual information and new words in context, make inferences, and interpret information in new contexts. Often is able to determine a selection’s main idea, identify its author’s purpose or viewpoint, and analyze its style and structure.

Grade 11

Usually understands stated information and ideas; often is able to infer implied meaning, draw conclusions, and interpret nonliteral language; and usually is able to make generalizations from or about a text, identify its author’s purpose or viewpoint, and evaluate aspects of its style or structure.

Proficient Performance in Mathematics

Grade 4

Is developing an understanding of many math concepts; usually is able to solve simple and complex word problems and use estimation methods; and can interpret data from graphs and tables.

Grade 8

Usually can understand math concepts and solve simple and complex word problems, sometimes can use estimation methods, and usually is able to interpret data from graphs and tables.

Grade 11

Sometimes applies math concepts and procedures, makes inferences with quantitative information, and solves a variety of quantitative reasoning problems.

Proficient Performance in Science

Grade 8

Sometimes understands ideas related to Earth, the universe, and the life sciences. Usually understands ideas related to the physical sciences and often can demonstrate the skills of scientific inquiry.

Grade 11

Sometimes makes inferences or predictions from data, judges the relevance and adequacy of information, and recognizes the rationale for and limitations of scientific procedures.