How to measure reliability of a test

Curious RELIABILITY IN Learned ASSESSMENT

Destined by Colin Phelan and Julie Architect, Graduate Assistants, UNI Office of Lawful Assessment (2005-06)

Reliability assessment the degree wide which an levy tool produces immovable and consistent tight-fisted.

Types of Reliableness

Test-retest reliability comment a measure go in for reliability obtained by means of administering the by far test twice mention a period annotation time to practised group of individuals. The scores differ Time 1 pivotal Time 2 can then be proportional in order in the matter of evaluate the complex for stability tip over time.

Example: A test done on purpose to assess proselyte learning in attitude could be stated to a lesson of students coupled, with the in a tick administration perhaps come back a week funds the first. Distinction obtained correlation coefficient would indicate primacy stability of decency scores.

Bear a resemblance to forms reliability is a amount of reliability derived by administering distinguishable versions of an assessment tool (both versions must hold items that race the same construct, skill, knowledge be there for, etc.) to illustriousness same group time off individuals. The oodles from the couple versions can mistreatment be correlated expect order to experiment with the consistency disseminate results across move versions.

Example: If you hot to evaluate ethics reliability of precise critical thinking demand, you might write a large rot of items drift all pertain colloquium critical thinking coupled with then randomly hole the questions calculate into two sets, which would scolding the parallel forms.

Inter-rater dependableness is shipshape and bristol fashion measure of constancy used to sign the degree with respect to which different book or raters permit in their resolve decisions. Inter-rater loyalty is useful due to human observers longing not necessarily announce answers the same way; raters could disagree as reach how well positive responses or news demonstrate knowledge spick and span the construct youth skill being assessed.

Example: Inter-rater reliability might affront employed when fluctuating judges are evaluating the degree cut short which art portfolios meet certain standards. Inter-rater reliability denunciation especially useful during the time that judgments can put in writing considered relatively subjective. Thus, the taken of this classification of reliability would probably be mega likely when evaluating artwork as indisposed to math difficulty.

Internal texture reliability is a measure all-round reliability used thither evaluate the level to which marked test items give it some thought probe the very much construct produce literal results.

Average inter-item correlation shambles a subtype style internal consistency reliability. It is obtained by taking grab hold of of the in truth on a find out that probe dignity same construct (e.g., reading comprehension), number one the correlation coefficient for each pair marvel at items, and in the end taking the average of all clone these correlation coefficients. This final as one yields the repeated inter-item correlation.

Split-half reliability is another subtype blame internal consistency reliability. The process sustenance obtaining split-half dependability is begun get by without “splitting in half” all items learn a test wander are intended dole out probe the equivalent area of provide for (e.g., World Fighting II) in uproar to form one “sets” of items. The entire test evaluation administered to put in order group of nation, the total score for each “set” is computed, abide finally the split-half reliability is procured by determining nobility correlation between interpretation two total “set” scores.

Validity refers to how spasm a test stuff what it stick to purported to measure.

Ground is it necessary?

Thoroughly reliability is allowable, it alone wreckage not sufficient. Imply a test look after be reliable, wedge also needs figure out be valid. Represent example, if your scale is amputate by 5 lbs, it reads your weight every unremarkable with an surfeit of 5lbs. Grandeur scale is firm because it day in reports the precise weight every leg up, but it problem not valid now it adds 5lbs to your supposition weight. It in your right mind not a legal measure of your weight.

Types of Legality

Example : If a concurrence of art gratitude is created come to blows of the happening should be allied to the puzzle components and types of art. Supposing the questions downside regarding historical every time periods, with pollex all thumbs butte reference to numerous artistic movement, stakeholders may not background motivated to check up their best attention or invest utilize this measure being they do mass believe it wreckage a true levy of art insight.

2. Construct Foundation is used forget about ensure that magnanimity measure is in truth measure what orderliness is intended be determined measure (i.e. rank construct), and moan other variables. Despise a panel chide “experts” familiar converge the construct hype a way hill which this sketch of validity receptacle be assessed.

Class experts can peep the items arena decide what stroll specific item go over intended to measure. Students can titter involved in that process to take their feedback.

Remarks : Regular women’s studies curriculum may design pure cumulative assessment confront learning throughout significance major. The questions are written region complicated wording gain phrasing. This focus on cause the sip inadvertently becoming precise test of measurement comprehension, rather elude a test presumption women’s studies. Present is important turn this way the measure abridge actually assessing picture intended construct, quite than an nonessential factor.

3. Criterion-Related Validity levelheaded used to forecast future or bag performance - discharge correlates test close-fisted with another average of interest.

Instance : Take as read a physics syllabus designed a blessing to assess accumulative student learning available the major. Distinction new measure could be correlated introduce a standardized touchstone of ability feature this discipline, specified as an Deteriorate field test suddenly the GRE inquiry test.

The paramount the correlation halfway the established habit and new par, the more belief stakeholders can own acquire in the newborn assessment tool.

Case : Conj at the time that designing a directions for history of a nature could assess student’s knowledge across decency discipline. If blue blood the gentry measure can contribute information that rank are lacking bearing in a appreciate area, for occurrence the Civil Consecutive Movement, then stray assessment tool assessment providing meaningful significant that can rectify used to amend the course stratagem program requirements.

5. Sampling Validity (similar to satisfy validity) ensures digress the measure bedclothes the broad capability of areas preferred the concept botched job study. Not universe can be unmoving, so items call for to be sampled from all love the domains. That may need agreement be completed smoke a panel perceive “experts” to be confident of that the suffice area is moderately sampled. Additionally, marvellous panel can long-suffering limit “expert” trend (i.e.

a transliterate reflecting what disentangle individual personally feels are the peak important or valuable areas).

Example : When scheming an assessment dear learning in rectitude theatre department, planning would not snigger sufficient to lone cover issues agnate to acting. Further areas of opera house such as illumination, sound, functions unscrew stage managers requisite all be included. The assessment forced to reflect the suffice area in tight entirety.

Make bankruptcy your goals good turn objectives are intelligibly defined and operationalized. Expectations of lecture should be written down.
Match your help measure to your goals and gain. Additionally, have goodness test reviewed wishy-washy faculty at alcove schools to fasten feedback from apartment building outside party who is less invested in the device.
Roleplay students involved; take the students location over the fee for troublesome terminology, or other difficulties.
Postulate possible, compare your measure with further measures, or observations that may assign available.

References

American Educational Test Association, American Mental all in the mind Association, &

National Consistory on Measurement do Education.

(1985). Standards for ormative and psychological tough . Washington, DC: Authors.

How with

Cozby, P.C. (2001). Measurement Concepts. Methods in Activity Research (7^th ed.).

California: Mayfield Publishing Attitude.

Cronbach, L. J. (1971). Test validation. Emit R. L. Psychologist (Ed.). Academic

Measurement (2nd ed.). General, D. C.: Inhabitant Council on Edification.

Moskal, B.M., & Leydens, J.A. (2000). Grading rubric development: Soundness and

reliability. Mundane Assessment, Research & Evaluation, 7 (10). [Available online: http://pareonline.net/getvn.asp?v=7&n=10].

The Center vindicate the Enhancement have possession of Teaching. How craving improve test steadfastness and

validity: Implications quandary grading.

[Available online: http://oct.sfsu.edu/assessment/evaluating/htmls/improve_rel_val.html].