Comment on Gow, A.J., Watson, R., Whiteman, M. & Deary, I.J. (2011). A Stairway to Heaven? Structure of the Religious Involvement Inventory and Spiritual Well-Being Scale. Journal of Religion & Health doi: 10.1007/s10943-010-9375-2

Gow, A. J., Watson, R., Whiteman, M., & Deary, I. J. (2011). A stairway to heaven? Structure of the religious involvement and spiritual well-being scale. Journal of Religion & Health. doi: 10.1007/s10943-010-9375-2.

Ligtvoet, R., van der Ark, L. A., te Marvelde, J. M., & Sijtsma, K. (2010). Investigating an invariant item ordering for polytomously scored items. Educational and Psychological Measurement, 70, 578–595.

Meijer, R. R. (2010). A comment on Watson, Deary, and Austin (2007) and Watson, Roberts, Gow, and Deary (2008): How to investigate whether personality items form a hierarchical scale? Personality and Individual Differences, 48, 502–503.

Molenaar, I. W., & Sijtsma, K. (2000). MSP5 for Windows: A program for Mokken scale analysis for polytomous items. iec ProGAMMA, Groningen.

Sijtsma, K., Meijer, R. R., & van der Ark, L. A. (2011). Mokken scale analysis as time goes by: An update for scaling practitioners. Personality and Individual Differences, 50, 31–37.

van der Ark, L. A. (2007). Mokken scale analysis in R. Journal of Statistical Software, 20(11), 1–19.

van der Ark, L. A. (2010). Getting started with Mokken scale analysis in R. http://spitswww.uvt.nl/~avdrark/research/mokkenstart.pdf . Retrieved 1 Oct 2010.

Watson, R., & Deary, I. J. (2009). Reply to: A comment on Watson, Deary, and Austin (2007) and Watson, Roberts, Gow, and Deary (2008): How to investigate whether personality items form a hierarchical scale? Personality and Individual Differences, 48, 504–505.

Watson, R., Deary, I., & Austin, E. (2007). Are personality trait items reliably more or less ‘difficult’? Mokken scaling of the NEO-FFI. Personality and Individual Difference, 43, 1460–1469.