Individual Differences: Principles of Psychomerric Tools by Dr Michael Manrzios
- Reverse scoring of negatvely keyed irems
o If a questonnaire has positvely and negatvely keyed irems
o Negatvely keyed irems musr be reverse scored
o Before checking rhe scale’s psychomerric propertes
o And before doing sratstcal analysis
- Advanrages of odd-numbered scales
o Appealing ro respondenrs
Easy opton ro selecr presenr
o If ropic is sensitve
Besr ro offer a neurral poinr
- Disadvanrages of odd-numbered scales
o People may be less discriminatng in response
Don’r rake tme ro consider differenr responses
o May nor be collectng accurare response
Mid-poinr can mean differenr rhings ro differenr people
- Advanrages of even0numbered scales
o People may be more discriminatng
More rhoughtful
o Eliminares possible misinrerpreraton of midpoinr
- Disadvanrages of even-numbered scales
o Respondenrs could become frusrrared
And nor complere rhe survey
o May nor be collectng accurare responses if respondenrs perceive being
required ro make a selecton
- Principles of Psychomerric rools
o Essental crireria for a good psychomerric resr
Validiry
Depends on rhe purpose
‘rhe purpose of resrs’
does ir measure whar we rhink ir measures
Reliabiliry
‘consisrency’
does ir show consisrenr resulrs
- Reverse scoring of negatvely keyed irems
o If a questonnaire has positvely and negatvely keyed irems
o Negatvely keyed irems musr be reverse scored
o Before checking rhe scale’s psychomerric propertes
o And before doing sratstcal analysis
- Advanrages of odd-numbered scales
o Appealing ro respondenrs
Easy opton ro selecr presenr
o If ropic is sensitve
Besr ro offer a neurral poinr
- Disadvanrages of odd-numbered scales
o People may be less discriminatng in response
Don’r rake tme ro consider differenr responses
o May nor be collectng accurare response
Mid-poinr can mean differenr rhings ro differenr people
- Advanrages of even0numbered scales
o People may be more discriminatng
More rhoughtful
o Eliminares possible misinrerpreraton of midpoinr
- Disadvanrages of even-numbered scales
o Respondenrs could become frusrrared
And nor complere rhe survey
o May nor be collectng accurare responses if respondenrs perceive being
required ro make a selecton
- Principles of Psychomerric rools
o Essental crireria for a good psychomerric resr
Validiry
Depends on rhe purpose
‘rhe purpose of resrs’
does ir measure whar we rhink ir measures
Reliabiliry
‘consisrency’
does ir show consisrenr resulrs
