Reverse Scoring Items
Just converting @eipi10's answer using tidyverse:
# Create same fake data: Three questions answered on a 1 to 5 scale
set.seed(1)
dat <- data.frame(Q1 = sample(1:5,10, replace=TRUE),
Q2 = sample(1:5,10, replace=TRUE),
Q3 = sample(1:5,10, replace=TRUE))
# Reverse scores in the desired columns (Q2 and Q3)
dat <- dat %>%
mutate(Q2Reversed = 6 - Q2,
Q3Reversed = 6 - Q3)
Here's an example with some fake data that you can adapt to your data:
# Fake data: Three questions answered on a 1 to 5 scale
set.seed(1)
dat = data.frame(Q1=sample(1:5,10,replace=TRUE),
Q2=sample(1:5,10,replace=TRUE),
Q3=sample(1:5,10,replace=TRUE))
dat
Q1 Q2 Q3
1 2 2 5
2 2 1 2
3 3 4 4
4 5 2 1
5 2 4 2
6 5 3 2
7 5 4 1
8 4 5 2
9 4 2 5
10 1 4 2
# Say you want to reverse questions Q1 and Q3
cols = c("Q1", "Q3")
dat[ ,cols] = 6 - dat[ ,cols]
dat
Q1 Q2 Q3
1 4 2 1
2 4 1 4
3 3 4 2
4 1 2 5
5 4 4 4
6 1 3 4
7 1 4 5
8 2 5 4
9 2 2 1
10 5 4 4
If you have a lot of columns, you can use tidyverse
functions to select multiple columns to recode in a single operation.
library(tidyverse)
# Reverse code columns Q1 and Q3
dat %>% mutate(across(matches("^Q[13]"), ~ 6 - .))
# Reverse code all columns that start with Q followed by one or two digits
dat %>% mutate(across(matches("^Q[0-9]{1,2}"), ~ 6 - .))
# Reverse code columns Q11 through Q20
dat %>% mutate(across(Q11:Q20, ~ 6 - .))
If different columns could have different maximum values, you can (adapting @HellowWorld's suggestion) customize the reverse-coding to the maximum value of each column:
# Reverse code columns Q11 through Q20
dat %>% mutate(across(Q11:Q20, ~ max(.) + 1 - .))