Here you can find the Story World Absorption Scale in its English, Dutch and German versions.
Each of these versions has been thoroughly validated.
Feel free to use this instrument in your research on narrative absorption. When you do, please refer to:
Kuijpers, M. M., Hakemulder, F., Tan, E. S., & Doicaru, M. M. (2014). Exploring absorbing reading experiences. Developing and validatin a self-report scale to measure story world absorption. *Scientific Study of Literature, 4*(4), 89-122. doi:10.1075/ssol.4.1.05kui
The version shared here was the last version of the paper (proofread stage) before publication.