本研究旨在尋求最適當的連結方法，再以此方法進行國小四至六年級 「倣尺性向測驗」的垂直等化。以國小六年級學生在「數量性向測驗」的表現為 共同尺尺來比較四種連結方法，結果發現: 1．難度:四年級和六年級難度在「數量關係」、「數量運算」分測驗進行連結時， 以平均數、標準差法最佳，而在「數系推理」分測驗，則以特徵曲線轉化法最優。 五年級和六年級難度在「數量關係」分測驗的連結，以特徵曲線轉化法最佳;但 在「數量運算」和「數系推理」分測驗的連結，則均以平均數、標準差法最佳。 而且，上述最佳連結方法的連結效果皆優於未連結前。 2．鑑別度:四年級和六年級鑑別度在「數量關係」、「數系推理」分測驗進行連 結時，以平均數、標準差法最佳;而在「數量運算」分測驗，則以重複強韌平均 數、標準差法最優。五年級和六年級鑑別度在「數量運算」、「數系推理」分測 驗的連結，以特徵曲線轉化法最佳;但在「數量關係」分測驗的連結，則以重複 強韌平均數、標準差法最佳。 3．四種連結方法中，以平均數、標準差法較佳，乃以此方法來進行國小四至六 年級數量性向測驗的垂直等化。

　　　　　The purpose of this study is to examine the possible effects of the four IRTlinking methods of the three subtests of elementary school Quantative AptitudeTest when across grades' comparison is necessary. The three-parameter-modellinking methods adopted were mean and sigma, robust mean and sigma, iterativerobust mean and sigma, and item characteristic curve transformation. The subtestsincluded were Quantative Relations, Quantative Commutation and Number Series.For each subtest, 15 anchor items were used for all fourth, fifth and sixthgraders. The estimated item parameters of the sixth graders were used as theevaluation criterion of the linking effects. The correlations between the fifth andsixth graders were around .85, but dropped to .65 for fourth and sixth gradersfor the difficulty parameter of the anchor items. The correlations for thediscrimination parameter were worse (around .63 and .10 respectively for thefifth and fourth graders). The linking results confirmed the concern of the linearassumption. Generally speaking, method of mean and sigma is suggested especiallywhen the the discrimination parameter can not be appropriately estimated. Thecomparison between two continuous grades is probably the most we can tolerantfor any linking method to be able to adjust the scale differences. The verticallinking across three grades is not recommended for the quantative aptitude test.