IMS Global QTI Glossary of Terms for Usage Data Item Statistics http://www.imsglobal.org/qti/qtiv2p2/itemstatisticsglossaryv1p0 A-Param IRT a parameter Index of item discrimination based on item response theory. Item Statistics, A-Param, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final AIS Average Item Score A group-dependent measure of item difficulty. Equal to the mean of the item scores for a group of individuals. For a rights-only dichotomously scored test, equivalent to the percent answering the item correctly (P-value). Distractor Statistics, AIS, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final B-Param IRT b parameter Index of item difficulty based on item response theory. Item Statistics, B-Param, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final C-Param IRT c parameter The lower asymptote of the item response function. Generally an index of guessing i.e. the probability of getting the item correct for very low ability examinees. Item Statistics, C-Param, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final D-Param IRT d parameter A measure of the dispersion of the item computed using the IRT method. Item Statistics, D-Param, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Fifths_Table_Highest Fifths_Table_Highest Count of examinees in the highest fifth of the test score distribution who selected the specified option. Item Statistics, Fifths_Table_Highest, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Fifths_Table_Lowest Fifths_Table_Lowest Count of examinees in the lowest fifth of the test score distribution who selected the specified option. Item Statistics, Fifths_Table_Lowest, IMS Global QTIv2.1 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Fifths_Table_Middle Fifths_Table_Middle Count of examinees in the middle fifth of the test score distribution who selected the specified option. Item Statistics, Fifths_Table_Middle, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Fifths_Table_Second_Highest Fifths_Table_Second_Highest Count of examinees in the second highest fifth of the test score distribution who selected the specified option. Item Statistics, Fifths_Table_Second_Highest, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Fifths_Table_Second_Lowest Fifths_Table_Second_Lowest Count of examinees in the second lowest fifth of the test score distribution who selected the specified option. Item Statistics, Fifths_Table_Second_Lowest, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final P-value P-value A group-dependent measure of item difficulty. It is equal to the percent answering the item correctly. Item Statistics, P-value, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final PHI Phi coefficient A group-dependent measure of item discrimination, Phi is the correlation of two dichotomous variables. In item analysis, it is generally the correlation between getting an item right or wrong and some dichotomous variable e.g. pass, fail. Item Statistics, PHI, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final PTbis r-pointbiserial A group-dependent measure of item discrimination, r-pointbiserial is the point biserial correlation between the score on a dichotomous item and a criterion which is a variable that can take many possible values, such as total score on the test. Item Statistics, PTbis, IMS Global QTIv2.1 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Polyserial Polyserial The polyserial correlation is the generalization of the biserial correlation for use with either dichotomous or polytomous items. For example, it may be the generalized form of the correlation with a criterion. It is the correlation of the item score with some continuous variable, usually the total score on the test. Item Statistics, Polyserial, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final Score_Conversion Score Conversion Table Raw scores and their corresponding converted values e.g. the values to be used in score reports. Item Statistics, Score_Conversion, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final rbis r-biserial A group-dependent measure of item discrimination, r-biserial is an estimate of the biserial correlation between a latent continuous variable hypothesised to underlie performance on a dichotomous item (i.e. item score) and a criterion which is a variable that can take many possible vales, such as total score on the test. Item Statistics, rbis, IMS Global QTIv2.2 IMS Global publisher IMS Global Learning Consortium Inc. 2015-03-01 Final QTIv2.2, Usage Data, Item Statistics Glossary en-US Description: The set of terms that would be used to collect the item statistics. This is the value that will be entered in the 'name' element. History: The first formal release of this QTI Glossary as part of QTIv2.2. author Colin Smythe (IMS Global, UK) and Mark McKell (IMS Global, USA) 1.0 Final Release publisher IMS Global Learning Consortium Inc. 2015-03-01 yes 2015 (c) IMS Global Learning Consortium Inc. XML