276:
83:. This is considered important because items vary in difficulty and the point-biserial correlation cannot attain its theoretical maxima unless the proportion correct is 0.50 (50% answering the item correctly). The biserial correlation has a correction that, in theory, avoids this issue. In practice, analysts should choose either the point-biserial or biserial and not try to compare, because the correction of the biserial will always produce a slightly larger magnitude as compared to the point-biserial.
52:, an item–total correlation is usually calculated for each item of a scale or test to diagnose the degree to which assessment items indicate the underlying trait. Assuming that most of the items of an assessment do indicate the underlying trait, each item should have a reasonably strong positive correlation with the total score on that assessment. An important goal of item analysis is to identify and remove or revise items that are not good indicators of the underlying trait.
94:, the IRI indexes the degree to which an item contributes true score variance to the exam observed score variance. In practice, a negative IRI indicates the relative degree which an item damages the reliability estimate and a positive value indicates the relative degree which it contributes towards a high reliability estimate.
63:
measured by the assessment. Exact values depend on the type of measure, but as a heuristic, a correlation value less than 0.2 indicates that the corresponding item does not correlate very well with the scale overall and, thus, it may be dropped. A negative value indicates that the item may be
68:
of the measure. Identifying and removing (or revising) poorly-performing items is a critical way that psychometric analysis can improve the quality of a measure.
317:
341:
336:
258:
222:
351:
21:
310:
185:
103:
346:
76:
356:
90:(IRI) is defined as the product of the point-biserial item-total correlation and the item standard deviation. In
303:
65:
87:
72:
60:
113:
91:
275:
80:
198:
166:
56:
254:
218:
183:
Churchill, G.A., (1979). "A paradigm for developing better measures of marketing constructs",
158:
287:
190:
150:
36:
analysis to diagnose assessment items that fail to indicate the underlying psychological
141:
Henrysson, Sten (1963-06-01). "Correction of item-total correlations in item analysis".
118:
330:
170:
108:
49:
37:
33:
194:
283:
25:
162:
29:
202:
154:
75:, the item-total correlation may be calculated as either a
291:
136:
134:
245:
243:
55:A small or negative item-correlation provides
311:
8:
71:When items are scored dichotomously, as in
44:The item-total correlation in item analysis
318:
304:
73:exams with correct and incorrect answers
59:that the item is not measuring the same
40:so that they can be removed or revised.
130:
215:The Cambridge Dictionary of Statistics
249:Allen, M.J., & Yen, W. M. (1979)
7:
272:
270:
24:between a scored item and the total
290:. You can help Knowledge (XXG) by
251:Introduction to Measurement Theory
14:
235:Discovering Statistics Using SPSS
274:
1:
186:Journal of Marketing Research
373:
342:Covariance and correlation
269:
195:10.1177/002224377901600110
77:point-biserial correlation
337:Comparison of assessments
66:psychometric reliability
352:Statistical reliability
286:-related article is a
237:. 2nd ed. London: Sage
88:item-reliability index
18:item–total correlation
213:Everitt, B.S. (2002)
114:Classical test theory
92:classical test theory
64:damaging the overall
217:, 2nd Edition, CUP.
81:biserial correlation
233:Field, A., (2005).
189:, 16(1) pp 64–73,
155:10.1007/BF02289618
57:empirical evidence
347:Statistical tests
299:
298:
364:
357:Statistics stubs
320:
313:
306:
278:
271:
261:
247:
238:
231:
225:
211:
205:
181:
175:
174:
138:
28:. It is an item
372:
371:
367:
366:
365:
363:
362:
361:
327:
326:
325:
324:
267:
265:
264:
248:
241:
232:
228:
212:
208:
182:
178:
140:
139:
132:
127:
100:
46:
12:
11:
5:
370:
368:
360:
359:
354:
349:
344:
339:
329:
328:
323:
322:
315:
308:
300:
297:
296:
279:
263:
262:
239:
226:
206:
176:
149:(2): 211–218.
129:
128:
126:
123:
122:
121:
119:Likert scaling
116:
111:
106:
104:Scale analysis
99:
96:
45:
42:
13:
10:
9:
6:
4:
3:
2:
369:
358:
355:
353:
350:
348:
345:
343:
340:
338:
335:
334:
332:
321:
316:
314:
309:
307:
302:
301:
295:
293:
289:
285:
280:
277:
273:
268:
260:
259:0-8185-0283-5
256:
253:, Wadsworth.
252:
246:
244:
240:
236:
230:
227:
224:
223:0-521-81099-X
220:
216:
210:
207:
204:
200:
196:
192:
188:
187:
180:
177:
172:
168:
164:
160:
156:
152:
148:
144:
143:Psychometrika
137:
135:
131:
124:
120:
117:
115:
112:
110:
109:Item analysis
107:
105:
102:
101:
97:
95:
93:
89:
84:
82:
78:
74:
69:
67:
62:
58:
53:
51:
50:item analysis
43:
41:
39:
35:
31:
27:
23:
19:
292:expanding it
281:
266:
250:
234:
229:
214:
209:
184:
179:
146:
142:
85:
70:
54:
47:
34:psychometric
17:
15:
22:correlation
331:Categories
284:statistics
125:References
26:test score
171:120534016
163:1860-0980
61:construct
30:statistic
98:See also
32:used in
203:3150876
20:is the
257:
221:
201:
169:
161:
282:This
199:JSTOR
167:S2CID
79:or a
38:trait
288:stub
255:ISBN
219:ISBN
159:ISSN
86:The
16:The
191:doi
151:doi
48:In
333::
242:^
197:,
165:.
157:.
147:28
145:.
133:^
319:e
312:t
305:v
294:.
193::
173:.
153::
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.