I am using 4 different scales in my survey: perceptions of diversity, perceptions of inclusion , work engagement and job satisfaction. 3 of them will be measured using 6 point Likert scale, however work engagement (UWES-9) is measured using 7 point Likert scale in the original study. I'm wondering can I use 6 point Likert scale to measure work engagement in order to keep consistency with other measures of my survey?