I am planning to apply Structural Equation Model and I have 5 level likert scale data for my variables (Strongly disagree, disagree, neutral, agree, strongly agree). I am learning R for empirical estimation. When I open my excel data, R reads the responses (Agree, Neutral, Strongly disagree etc) as character that is understandable as the data is in the form of text. After some research I found out that first I need to convert the character variables into factors and then into numeric values. So I did that but R didn't take into account the order of factors. For instance, order should be: Strongly disagree =1, disagree=2, neutral=3, agree=4, strongly agree=5, because I didn't use the levels argument in my command. Now when I use the levels argument, see below:
a3 = as.factor(mydata$qa3, levels = c('Strongly disagree', 'Disagree', 'neutral', 'Agree', 'stringly disagree'))
I am getting the following error.
Error in as.factor(mydata$qa3, levels = c("Strongly disagree", "Disagree", :
unused argument (levels = c("Strongly disagree", "Disagree", "neutral", "Agree", "stringly disagree"))
I have two questions in this regard:
1. How can I convert these characters into ordered numeric for further data analysis?
2. Is there a way I can do it for several variables at once instead of doing it one by one?
Thank You!
Hello!
## Create fake data
set.seed(123)
nrow
this link may helpful to you.
https://stackoverflow.com/questions/28771750/how-to-convert-a-factor-variable-into-a-numeric-using-r
Hello! Take a look here:
https://stackoverflow.com/questions/38724850/converting-likert-data-to-numeric-across-a-data-frame
First, here's why you would have to convert to character before converting to numeric:
Lets say we have a factor that contains a handful of numbers
x = factor(c(1,2,7,7))
you can inspect how this is represented in R like so:
unclass(x)
#> [1] 1 2 3 3
#> attr(,"levels")
#> [1] "1" "2" "7"
and you would see that there are 3 levels, and that the values are represented as indexes to those 3 levels. Furthermore if you call as.numeric() directly, you get the index vector and not the values you were hoping for:
as.numeric(x)
#> [1] 1 2 3 3
On the other hand, if you have a likert scale, and the factor levels are in the correct order:
f = factor(c("agree","agree","somewhat agree","somewhat agree","somewhat disagree","disagree","disagree"))
levels(f)
#> [1] "agree" "disagree" "somewhat agree" "somewhat disagree"
you may actually want the index:
#> as.numeric(f)
[1] 1 1 3 3 4 2 2
If, however, your levels are out of order, as in:
f = factor(sample(c("agree","somewhat agree","somewhat disagree","disagree"),
20,
TRUE))
levels(f)
#> [1] "agree" "disagree" "somewhat agree" "somewhat disagree"
then instead of calling as.numeric(as.character(f)) (which makes no sense in this case), you'll want to re-order the factor levels, and then call as.numeric, like so:
as.numeric(factor(f,
# specifify the levels in the correct order:
levels=c("agree",")
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