Adding correlations between items

[Vera Schäfer]

Hello :)

I would like to improve my bifactor model by allowing two items to correlate. However i can only find ways to allow covariance for factors.

Do you have suggestion ?

Thanks in advance :)

[Seongho Bae]

Basically, IRT doesn't allow that what I learned. Instead, You can use two options.

One is making a new method factor for allowing item local dependence, the other one removes an unfit item where item fit indices with itemfit() function.

Seongho

2017년 7월 5일 수요일 오후 5시 20분 9초 UTC+9, Vera Schäfer 님의 말: