Bell curve grading

Bell curve grading

In education, grading on a bell curve (or simply known as curving) is a method of assigning grades designed to yield a desired distribution of grades among the students in a class. Strictly speaking, grading "on a bell curve" refers to the assigning of grades according to the frequency distribution known as the Normal distribution (also called the Gaussian distribution), whose graphical representation is referred to as the Normal curve or the bell curve. Because bell curve grading assigns grades to students based on their "relative" performance in comparison to classmates' performance, the term "bell curve grading" came, by extension, to be more loosely applied to any method of assigning grades that makes use of comparison between students' performances, though this type of grading does not necessarily actually make use of any frequency distribution such as the bell-shaped Normal distribution.

In true use of bell curve grading, students' scores are scaled according to the frequency distribution represented by the Normal curve. The instructor can decide what grade occupies the center of the distribution. This is the grade an average score will earn, and will be the most common. Traditionally, in the ABCDF system this is the 'C' grade. The instructor can also decide what portion of the frequency distribution each grade occupies and whether or not high and low grades are symmetrically assigned area under the curve (i.e. if the top 15% of students earn an 'A,' do the bottom 15% fail or might only the bottom 5% fail?). In a system of pure curve grading, the number of students who will receive each grade is already determined at the beginning of a course.

Other forms of "curved" grading vary, but one of the most common is to add to all students' "absolute" scores the difference between the top student's score and the maximum possible score. For example, if the top score on an exam is 55 out of 60, all students' absolute scores (meaning they have not been adjusted "relative" to other students' scores in any way) will be increased by 5 before being compared to a pre-determined set of grading benchmarks (for example the common A>90%>B>80% etc. system). This method prevents unusually hard assignments (usually exams) from unfairly reducing students' grades but relies on the assumption that the top student's performance is a good measure of an assignment's difficulty.

In the U.S., strict bell-curve grading is unusual at the elementary and secondary school levels (both in age-based grade placement and in standardized testing), but common at the university level.

Benefits and shortcomings

Viewed practically, curved grading is beneficial (to test-givers, not test-takers) because it automatically factors in the difficulty a group of test-takers had with a test. If the majority of students have high (or low) scores then the middling grade will be adjusted there and higher or lower grades awarded based on this performance. In addition, the curve ameliorates the problem of deciding grades that fall very near a grade margin. Clustering of marks establish where the margin should be placed.

However, grading in this way is essentially normative; scores are referenced to the performance of group member. There must always be at least one student who has a lower score than all others, even if that score is quite high when evaluated against specific performance criteria or standards. Conversely, if all students perform poorly relative to a larger population, even the highest graded students may be failing to meet standards. Thus, curved grading makes it difficult to compare groups of students to one another.

An additional shortcoming is that many students can easily become confused between their relative and absolute grades.Fact|date=August 2008

ee also

*Grade (education)
*List of law school GPA curves

Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Bell curve — can refer to:* Normal distribution, whose density function graph is a bell shaped curve * The Bell Curve , a book by Richard J. Herrnstein and Charles Murray * Bell curve grading, a method of evaluating scholastic performance …   Wikipedia

  • Bell — may refer to: Devices that produce sound * Altar bell, a bell rung during the Catholic Mass. * Bell character, a character that produces an audible signal at a terminal. * Bell effect, a musical technique similar to an arpeggio. * Bell… …   Wikipedia

  • Grading on a curve — In education, grading on a curve (also known as curved grading or simply curving) is a statistical method of assigning grades designed to yield a pre determined distribution of grades among the students in a class. The term curve refers to the… …   Wikipedia

  • curve — {{Roman}}I.{{/Roman}} noun 1 line or surface that bends ADJECTIVE ▪ gentle, graceful, slight, smooth, soft ▪ sharp, tight ▪ sweepi …   Collocations dictionary

  • List of law school GPA curves — Many, or perhaps most, law schools in the United States grade on a curve. The process generally works within each class, where the instructor grades the work, and then ranks the initial grades, adding to and subtracting from the initial grades so …   Wikipedia

  • Normal distribution — This article is about the univariate normal distribution. For normally distributed vectors, see Multivariate normal distribution. Probability density function The red line is the standard normal distribution Cumulative distribution function …   Wikipedia

  • Grade (education) — GPA redirects here. For other uses, see GPA (disambiguation). Academic grading Africa Egypt • Kenya • Morocc …   Wikipedia

  • Outcome-based education — (OBE) is a recurring education reform model. It is a student centered learning philosophy that focuses on empirically measuring student performance, which are called outcomes. OBE contrasts with traditional education, which primarily focuses on… …   Wikipedia

  • Standards-based assessment — A standards based test is one based on the outcome based education or performance based education philosophy. [ [ 01 18 06.html] January 18 2006 Standards Based Test draws plan for awarenessJackie… …   Wikipedia

  • Education reform — is the process of improving public education. Small improvements in education theoretically have large social returns, in health, wealth and well being. Historically, reforms have taken different forms because the motivations of reformers have… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”