Ultimately, a Likert scale question may be arranged vertically or horizontally.
However, there have been researchers investigating the possibility of something called a left-side bias when displaying a Likert scale question horizontally. Essentially, left-side bias means that when placing answer options on the left side of the Likert scale, there is a tendency among respondents to select these options, said tendency being somewhat stronger for positive options on the left side than negative options.
Furthermore, there has been equivalent research showing a similar, yet even stronger selection bias for vertical Likert scales as respondents tend to skip lower displayed answer options and more often select the top options.
Based on these statements, certain scale layouts appear more suitable to avoid survey bias and sloppy question answering than others.
Horizontal Likert Scale:
According to the Likert scale bias matrix, to keep the bias as low as possible in a horizontal order, it appears best to place negative attitude options on the left side of the scale and positive attitude options on the right side of the scale.
Vertical Likert Scale:
According to the Likert scale bias matrix, to keep the bias as low as possible in a vertical order, it appears best to place negative attitude options at the top of the scale and positive attitude options at the bottom of the scale.
In addition, Likert scales can be modified to hold 7 or more answer options depending on the level of refinement that is required for a specific question or survey.
Horizontal 7-point Likert Scale:
Vertical 7-point Likert Scale: