Raw to Scale Score Conversion

[Amir_kth]

Dear Friends,

 

How can I convert raw scores to scale scores in paper or computer based TOEFL? For example, assume we have 50 questions in listening section of paper-based TOEFL, with 30 correct answers. I want to know this result corresponds to which score in [31, 68] interval.

Although mapping the interval: [0, 50] to [31, 68] yeilds to the following relation, it seems to me that the results obtained by the following relation are more than actual test results:

 

scale score=[(68-31)/50]*raw score+31

 

I also aware of this point that the scores which are reported by ETS are based on some statistical calculations, but is any rule of thumb in this regard?

 

Thanks for your kind attention.

[jose]

Dear Friends,

 

How can I convert raw scores to scale scores in paper or computer based TOEFL? For example, assume we have 50 questions in listening section of paper-based TOEFL, with 30 correct answers. I want to know this result corresponds to which score in [31, 68] interval.

Although mapping the interval: [0, 50] to [31, 68] yeilds to the following relation, it seems to me that the results obtained by the following relation are more than actual test results:

 

scale score=[(68-31)/50]*raw score+31

 

I also aware of this point that the scores which are reported by ETS are based on some statistical calculations, but is any rule of thumb in this regard?

 

Thanks for your kind attention.

 

At PBT each correct answer counts equal toward the score, no matter if it was easy or difficult