+ Reply to Thread
Results 1 to 7 of 7

Thread: How to calculate the overall mean of several Likert scale data?

  1. #1
    Points: 373, Level: 7
    Level completed: 46%, Points required for next Level: 27

    Posts
    4
    Thanks
    2
    Thanked 0 Times in 0 Posts

    Post How to calculate the overall mean of several Likert scale data?




    Hi, I have a set of questionnaire as follow:

    Perceived Usefulness Rating(5-point Likert Scale)

    PU01
    PU02
    PU03
    ...
    I used SPSS to compute the mean of these data. The output as follow:

    Descriptive Statistic N Minimum Maximum Mean Standard Deviation

    PU01
    PU02
    PU03
    Valid(listwise)

    The result show that mean is compute for each PU01, PU02, PU03. This is not the result that I desired.

    The question is how can I calculate the mean of the PU01, PU02, PU03 under a category which is Perceived Usefulness?

    *English is not my native language.

    Thank You.

  2. #2
    Points: 2,795, Level: 32
    Level completed: 30%, Points required for next Level: 105

    Location
    Amsterdam, The Netherlands
    Posts
    64
    Thanks
    19
    Thanked 9 Times in 9 Posts

    Re: How to calculate the overall mean of several Likert scale data?

    You need to give a value to your Likert-scale items. That is to say:

    Strongly agree = 5
    Agree = 4
    Neither agree nor disagree =3
    Disagree = 2
    Strongly disagree = 1

    Example:

    Lets say respondent 1 answered disagree, respondent 2 answered strongly disagree, and respondent 3 answered neither agree nor disagree.

    In this case, you have three "converted" values: 2, 1, 3. Its mean or average equals 2.

    I believe it is more meaningful to use a different scale to 1,2,3,4,5 for your code. If you use multiples, 2.5, 5.0, 7.5, 10, you get somewhat of a more meaningful scale in my opinion. Although I am unsure whether there would be any serious statistical implications.

    To learn more about this technique in SPSS, I recommend:

    http://www.uni.edu/its/support/article/604

    All the best,

    Ramon

  3. #3
    Points: 3,024, Level: 33
    Level completed: 83%, Points required for next Level: 26
    SmoothJohn's Avatar
    Location
    Edmonton, Canada
    Posts
    165
    Thanks
    11
    Thanked 12 Times in 10 Posts

    Re: How to calculate the overall mean of several Likert scale data?

    But what would such a mean mean?

  4. #4
    Points: 2,843, Level: 32
    Level completed: 62%, Points required for next Level: 57

    Posts
    124
    Thanks
    0
    Thanked 56 Times in 50 Posts

    Re: How to calculate the overall mean of several Likert scale data?

    If you're using a validated scale the original authors will have provided instructions on how it should be scored. If you're asking for advice on how to obtain a mean score across the items in SPSS then you can run the following syntax (adjusting for however many items in the scale):

    Code: 
    compute PUmean = mean(PU01 to PU03).
    exe.
    Last edited by helicon; 03-05-2012 at 04:27 PM.

  5. #5
    Points: 5,259, Level: 46
    Level completed: 55%, Points required for next Level: 91
    SiBorg's Avatar
    Posts
    255
    Thanks
    71
    Thanked 25 Times in 22 Posts

    Re: How to calculate the overall mean of several Likert scale data?

    If you're using a Likert scale, consider using the median rather than the mean, as you're dealing with ordinal rather than continuous data.

  6. #6
    Probably A Mammal
    Points: 19,108, Level: 87
    Level completed: 52%, Points required for next Level: 242
    bryangoodrich's Avatar
    Location
    Sacramento, California, United States
    Posts
    2,205
    Thanks
    292
    Thanked 495 Times in 450 Posts

    Re: How to calculate the overall mean of several Likert scale data?

    Quote Originally Posted by parsec2011 View Post
    I believe it is more meaningful to use a different scale to 1,2,3,4,5 for your code. If you use multiples, 2.5, 5.0, 7.5, 10, you get somewhat of a more meaningful scale in my opinion. Although I am unsure whether there would be any serious statistical implications.
    Psychology isn't my area, but I'm curious to know what research there is to back that up or that discusses this issue? It's something I've wondered about. I know more ratings (say, 7-point scale) can give you a finer partition of the provided space (metric), so numerical values like means more closely match their real-number space counterparts, but I would like to find some articles that talk about using different numerical encodings and their benefits, such as your suggested multiples.

  7. #7
    R must die
    Points: 25,627, Level: 96
    Level completed: 28%, Points required for next Level: 723
    Awards:
    Activity Award
    noetsi's Avatar
    Posts
    4,632
    Thanks
    303
    Thanked 734 Times in 704 Posts

    Re: How to calculate the overall mean of several Likert scale data?


    I think in practice it would depend heavily on how people interpreted those codes. For an ordinal scaled variable I am not sure of the logic of assigning any particular scale more or less value. If you chose to interpret a likert scale as interval like (as is often done, but much debated) the mean of the later scale would be more confusing or less simple in any case.
    "..which is what 99.999% of people do so you would be wrong, but you would be wrong alongside with everyone else which somehow makes you... you know, not-so-wrong. "

+ Reply to Thread

           




Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts






Advertise on Talk Stats