Dr. Christine Pereira
Useful tools and functions for survey data Part 3
BEEC
Dr. Christine Pereira Academic Skills Team (ASK) ask@brunel.ac.uk
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» Entering data from a survey » Recode variables
» Reliability test using Cronbach’s alpha » Compute a total score and mean score
» Select cases to analyse
Dr. Christine Pereira
» Summarise responses from multi-response questions
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What are the variables?
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Select ‘ONE’ Response Questions What is your main mode of transport to Uni during the week?
What is your age? (please tick one)
18-25 26-35 36-45 46-55 56+
(please tick one)
Car Bus Tube Rail Walk Cycle Other: ____________ Dr. Christine Pereira
Yes
No
Do you try to minimise your carbon footprint? (please tick one) What is your gender? (please circle one)
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Male
Female
Single response survey questions. Each question is a new variable.
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Dr. Christine Pereira
Select ONE response Participant
Gender
Age Group
Mode
CO2
1
Male
36-45
Car
No
2
Male
26-35
Tube
Yes
3
Female
46-55
Car
No
4
Male
18-25
Tube
Yes
5
Female
26-35
Rail
Yes
Single response survey questions. Each question is a new variable. ASK at Brunel (2014-15)
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Multiple Response Questions Which mode(s) of transport do you usually take to get to Uni during the week?
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(please tick all that apply) Car Bus Tube Rail Walk Cycle Other: ____________
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‘tick all…’ instead of ‘tick one’
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Dr. Christine Pereira
Multiple response Participant
Transport
1
Car
2
Bus, Tube
3
Car
4
Tube, Rail, Walk
5
Bus, Rail
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Can we enter responses like this?
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Dr. Christine Pereira
Multiple response Participant
Transport
1
Car
2
Bus, Tube
3
Car
4
Tube, Rail, Walk
5
Bus, Rail
ASK at Brunel (2014-15)
Can we enter responses like this? Why not?
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Dr. Christine Pereira
Multiple response Participant
Transport
1
Car
2
Bus, Tube
3
Car
4
Tube, Rail, Walk
5
Bus, Rail
Can we enter responses like this? Why not?
Only ONE response per cell for statistical analysis ASK at Brunel (2014-15)
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Dr. Christine Pereira
Multiple response Participant
Car
Bus
Tube
Rail
Walk
Cycle
1
Yes
No
No
No
No
No
2
No
Yes
Yes
No
No
No
3
Yes
No
No
No
No
No
4
No
No
Yes
Yes
Yes
No
5
No
Yes
No
Yes
No
No
Multiple response survey question Each response is a new variable ASK at Brunel (2014-15)
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Dr. Christine Pereira
Multiple response Participant
Car
Bus
Tube
Rail
Walk
Cycle
1
Yes
No
No
No
No
No
2
No
Yes
Yes
No
No
No
3
Yes
4
No
No
Yes
Yes
Yes
No
5
No
Yes
No
Yes
No
No
Yes = They travel by car No No No No No = They do not travel by car
No
Multiple response survey question Each response is a new variable ASK at Brunel (2014-15)
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Dr. Christine Pereira
Multiple response Participant
Car
Bus
Tube
Rail
Walk
Cycle
1
Yes
No
No
No
No
No
2
No
Yes
Yes
No
No
No
3
Yes
No
4
No
No
Yes
Yes
Yes
No
5
No
Yes
No
Yes
No
No
Yes = They travel by bus No No No No No = They do not travel by bus
Multiple response survey question Each response is a new variable ASK at Brunel (2014-15)
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Ranked Response Questions Âť Obtain preferential judgements or opinions. Rank the following subjects from 1-5 based on how much you like them. (1 = Favourite, 5 = Least favourite)
Rank in order of importance, from 1-5, the following features when considering a destination for your holiday.
Dr. Christine Pereira
(1 = Most important)
History Science Math Writing IT
I’ve never been before Weather Surroundings Cost Accommodation
These also are multiple response questions ASK at Brunel (2014-15)
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Dr. Christine Pereira
Ranked multiple response Participant
Never been
Weather
Surroundings
Cost
Accommodation
1
Most Impt
4
2
3
5
2
5
2
3
Most Impt
4
3
5
Most Impt
2
4
3
4
3
4
5
Most Impt
2
5
4
2
Most Impt
5
3
Multiple response survey question Each response is a new variable ASK at Brunel (2014-15)
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Scaled Response Questions » Obtain preferential judgements or opinions Likert scale: Level of agreement Other scales: Level of importance or satisfaction
Dr. Christine Pereira
How important are the following when considering where to live?
(circle one)
Very Important
Important
I don’t know
Unimportant
Very Unimportant
Cost
1
2
3
4
5
Distance to Uni
1
2
3
4
5
Distance to work
1
2
3
4
5
I feel safe
1
2
3
4
5
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Dr. Christine Pereira
Scaled multiple response Participant
Cost
Dist Uni
Dist Work
Safety
1
Very Impt
Important
I don’t know
Important
2
Important
Very Impt
Very Impt
Important
3
Unimportant
Very Impt
Important
Very Impt
4
Unimportant
I don’t know
Important
Important
5
Very Impt
Important
Important
Very Impt
Single response survey questions. Each question is a new variable. ASK at Brunel (2014-15)
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Dr. Christine Pereira
Click here
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Dr. Christine Pereira
Save these SPSS data files: EmployeeSurvey.sav Reliability data.sav ASK at Brunel (2014-15)
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Dr. Christine Pereira
Reverse coding or regroup responses
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Dr. Christine Pereira
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Old value
New value
Current coding
Reverse coding
1
Strongly Disagree
5
Strongly Disagree
2
Disagree
4
Disagree
3
Undecided
3
Undecided
4
Agree
2
Agree
5
Strongly Agree
1
Strongly Agree 20
Select variable to recode
Selected variable
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Click
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Name and Label new variable
New variable
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Click
Lastly Click here ASK at Brunel (2014-15)
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Old value
New value
Dr. Christine Pereira
Click ‘Add’
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Dr. Christine Pereira
http://www.statstutor.ac.uk/resources/uploaded/reversecodev20.mp4 ASK at Brunel (2014-15)
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Dr. Christine Pereira
ASK at Brunel (2014-15)
Old value
New value
Current coding
Regroup coding
1
Strongly Disagree
2
Disagree
3
Undecided
4
Agree
5
Strongly Agree
1
Disagree or Strongly Disagree
2
Undecided
3
Agree or Strongly Agree
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Select variable to recode
Selected variable
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Click
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Name and Label new variable
New variable
Dr. Christine Pereira
Click
Lastly Click here ASK at Brunel (2014-15)
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Old value
New value
Dr. Christine Pereira
Click ‘Add’
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Dr. Christine Pereira
http://www.statstutor.ac.uk/resources/uploaded/reducegroupsv20.mp4 ASK at Brunel (2014-15)
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Dr. Christine Pereira
Measuring reliability of items
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» Cronbach’s Alpha measures internal consistency between items in a scale
» Make sure not to mix positively and negatively worded questions – Alpha will be negative.
Dr. Christine Pereira
Reverse code variables if needed
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Select variables Click
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Selected variables
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Click
*Optional: Name the scale ASK at Brunel (2014-15)
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Dr. Christine Pereira
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Dr. Christine Pereira
http://youtu.be/NvGG38N0P7c ASK at Brunel (2014-15)
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1
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2
Should be >=.70 If less than 10 items, it should be >0.5 ASK at Brunel (2014-15)
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Dr. Christine Pereira
3
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The correlation of every item in the scale with every other item. ASK at Brunel (2014-15)
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Dr. Christine Pereira
The mean inter-item correlation. If Alpha is low (due to few items) report this value too. ASK at Brunel (2014-15)
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Dr. Christine Pereira
The correlation of each item with all other items combined. Should be >0.40 ASK at Brunel (2014-15)
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Dr. Christine Pereira
Cronbach’s Alpha if the item is deleted from the scale. ASK at Brunel (2014-15)
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Dr. Christine Pereira
http://youtu.be/KODQPg-48jA ASK at Brunel (2014-15)
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Dr. Christine Pereira
Using the ‘Compute variable’ tool
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Dr. Christine Pereira
Name the new variable
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Dr. Christine Pereira
Add variables together with +
Variables in dataset ASK at Brunel (2014-15)
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Dr. Christine Pereira
Click OK ASK at Brunel (2014-15)
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Dr. Christine Pereira
Name the new variable
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Dr. Christine Pereira
Double click
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Dr. Christine Pereira
Replace ? with variable names Put a , between each variable
Variables in dataset ASK at Brunel (2014-15)
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Dr. Christine Pereira
Click OK ASK at Brunel (2014-15)
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Numeric Expression: MEAN(LifeSatis1, LifeSatis2, LifeSatis3, LifeSatis4, LifeSatis5)
Calculates a mean for every participant, even if they are missing 1 or more of the LifeSatis scores Numeric Expression: Dr. Christine Pereira
MEAN.2(LifeSatis1, LifeSatis2, LifeSatis3, LifeSatis4, LifeSatis5)
Calculates a mean for every participant only if they have at least 2 of the LifeSatis scores ASK at Brunel (2014-15)
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Numeric Expression: MEAN.3(LifeSatis1, LifeSatis2, LifeSatis3, LifeSatis4, LifeSatis5)
Calculates a mean for every participant, only if they have all 3 competency scores
Dr. Christine Pereira
This number can be between 1 and the number of items being averaged
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Dr. Christine Pereira
http://www.statstutor.ac.uk/resources/uploaded/computemeanv20-2.mp4 ASK at Brunel (2014-15)
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Dr. Christine Pereira
Select specific cases of the data to analyse
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» Select specific cases of your data to analyse
» Example using Employeesurvey.sav Select only females for analysis + Gender = 1
Select only semi- and highly skilled participants + Rated skill = 3 or Rated skill = 4
Select only highly skilled females Dr. Christine Pereira
+ Gender = 1 and Rated skill = 4
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Dr. Christine Pereira
Select only Females
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Click the
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button
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Female is coded as 1
Dr. Christine Pereira
Select Gender
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A new variable called filter_$
Not selected corresponds to males
Dr. Christine Pereira
Males are excluded from any analysis
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Select only fairly skilled and highly skilled participants
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Fairly skilled coded 3 Highly skilled coded 4
Select Rated Skill
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Unskilled and Semi-skilled excluded
A new variable called filter_$
Dr. Christine Pereira
Not selected corresponds to Unskilled and semi-skilled
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Dr. Christine Pereira
Select only highly skilled females
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Dr. Christine Pereira
Highly skilled coded as 4 Female is coded as 1
Select Gender & Rated Skill
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Only highly skilled females not excluded
A new variable called filter_$
Dr. Christine Pereira
Selected corresponds to highly skilled and female
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Dr. Christine Pereira
https://www.youtube.com/watch?v=NUSam9mRiV0 ASK at Brunel (2014-15)
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Dr. Christine Pereira
Summarise responses to multi-response questions
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Dr. Christine Pereira
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Dr. Christine Pereira
‘1’ means they ticked that option
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Dr. Christine Pereira
Move the set you want to analyse to the right.
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