To the Editor:

We read with interest the article by Arpacı and Esgi titled “Psychometric properties of the Turkish version of the Smartphone Addiction Inventory (SPAI)” (Arpaci and Esgi 2018).

Original SPAI was developed by Lin et al. in 2014 to measure the smartphone addiction. The validity and reliability study of the scale was done which was prepared as 4-point Likert and 26-item (Lin et al. 2014). The Turkish validity and reliability of SPAI was done by Arpacı and Esgi in 2018 and published in Current Psychology.

This letter is written to point the inconsistency between the response categories of the original and adapted form of the SPAI.

The original of SPAI which was developed in 4-point Likert type was defined as 5-point Likert in the measures part of the method section of Arpacı and Esgi’s article (Arpaci and Esgi 2018). It is not clear if there was a typo in the text or a methodological mistake. If a structural change was made on the Turkish version of the scale, this is an important methodological case. But, the authors did not provide a justification and explanation for the change they made. Table 5 of the Arpacı and Esgi’s article also did not include the responses in Likert-type categories in the Turkish version of the scale (Arpaci and Esgi 2018). Therefore, this situation is confusing for readers.

Modifications can be made to reduce the number of questions, to facilitate the answering, to improve the scope or to increase the validity / reliability. In this case, the reason for making the changes, how it will affect the interpretation of the results should be explained, and this change should be defined by the version number in the title of the scale.

We think it would be useful to make a statement about this issue in the article by the authors.