Scaling Techniques

1
Scaling Techniques

• Sharon Paynter
• Spring 2007
• Manheim Ch 9

2
Scaling

• Combination of a number of relatively narrow
  indicators into a single, summary measure that we
  take to represent the broader, underlying concept
  
• Scale Unifying measure that represents
  underlying concept
• Scale Score Degree to which any given case
  manifests an underlying concept

3
Validity

• Does our SCALE measure what we intended it to
  measure
• Face
• is there reason to believe that each specific
  question is related to concept we are measuring
• Collectively the components capture full
  essence
• Does it make sense to combine these indicators?
• Does the label makes sense once they are combined

4
Reliability

• Are various research questions actually related
  to one another in a consistent and meaningful
  manner
• Not designed to separate groups
• Designed to tell us more about each group
• How would you rate your political view in the
  following areas
• Liberal Moderate
  Conservative
• 1 2 3 4 5
• (1) Social Policy (4) Military Policy
• (2) Fiscal Policy (5) Domestic Policy
• (3) Foreign Policy

5
Likert Scaling p159

• Series of statements require value judgment
• Summary score take average of all items
• In general higher score more of characteristic
• Good reliability high correlation between items
• Strongly Agree
• Agree
• Neutral
• Disagree
• Strongly Disagree

6
Guttman Scaling p161

• Attitudes and behaviors are related in logical
  hierarchical pattern (like a ladder)
• Must begin at bottom and work your way up
• Voted in Presidential Election
• Voted in Local Election
• Made campaign contribution
• Volunteered for campaign
• Ran for political office
• http//www.socialresearchmethods.net/kb/scalgutt.p
  hp

7
Thurstone Scaling p165

• http//www.socialresearchmethods.net/kb/scalthur.p
  hp
• Develop long list of items
• Identify judges from target community
• Judges rank each item based on how much it
  related to primary construct
• Each item assigned score (mean/median)
• Items assigned to several categories dropped
• 15-20 final items selected
• High agreement from judges
• Spans the range (favorable to unfavorable)
• Respondents asked
• Which of the following do you agree with
• Which 2 or 3 statements are closest to your view
  of ..

8
Semantic Differential p166

• Used to construct and evaluate definitions rather
  than measure general concepts
• Sets of adjective pairs to describe concept
• Respondents rate their feelings on 7 point scale
  between the two adjectives