How to normalize acceptability scores

In acceptability judgment experiments, participants make use of an acceptability scale (most commonly the 7-point Likert scale) in various ways; some people use 1 and 7 exclusively, while other people stick to 3 through 5. In order to normalize their scores, it is common to convert raw acceptability to z-scores (standard scores). The code for z-score conversion is as follows:

data <- read.csv('./sampledata.csv')
data <- data %>% group_by(Subj_id) %>% mutate(Z_score = (Score - mean(Score)) / sd(Score))

#before
head(data$Score, 5)

## [1] 6 2 3 7 2

#after
head(data$Z_score, 5)

## [1]  1.2657845 -0.7344676 -0.2344045  1.7658475 -0.7344676