Scale library · Consumer behavior
Theory of Planned Behavior (TPB) scale: Ajzen (1991)
TPB was proposed by Ajzen (1991), extending the theory of reasoned action with perceived behavioral control. Intention to perform a behavior depends on attitude toward the behavior, subjective norm and perceived behavioral control, and intention is the immediate antecedent of behavior. Ajzen publishes no fixed item set but guidance for writing items for each specific behavior, so the items here come from Ajzen's guidance and the manual by Francis et al. (2004). It frames many theses on buying organic food, online shopping, entrepreneurship and green consumption.
Cite the original, not the blog.
- Model or scale: TPB
- Constructs: 4
- Items: 16 (5 reverse-coded)
Original English items
Items marked (R) are reverse-coded: recode them before computing reliability or scale scores. Replace bracketed placeholders such as [system] with the name of the system, brand or organization you study.
Attitude toward the Behavior (ATT, 4 items)
| Code | Item wording | Reverse-coded |
|---|---|---|
| ATT1 | [Performing the behavior] is: harmful 1 2 3 4 5 6 7 beneficial | No |
| ATT2 (R) | [Performing the behavior] is: good 1 2 3 4 5 6 7 bad | Yes |
| ATT3 (R) | [Performing the behavior] is: pleasant (for me) 1 2 3 4 5 6 7 unpleasant (for me) | Yes |
| ATT4 | [Performing the behavior] is: worthless 1 2 3 4 5 6 7 useful | No |
Subjective Norm (SN, 5 items)
| Code | Item wording | Reverse-coded |
|---|---|---|
| SN1 (R) | Most people who are important to me think that I should 1 2 3 4 5 6 7 I should not [perform the behavior]. | Yes |
| SN2 | It is expected of me that I [perform the behavior]. | No |
| SN3 | I feel under social pressure to [perform the behavior]. | No |
| SN4 | People who are important to me want me to [perform the behavior]. | No |
| SN5 | Most people like me [performed the behavior]. (unlikely 1 2 3 4 5 6 7 likely) | No |
Perceived Behavioral Control (PBC, 4 items)
| Code | Item wording | Reverse-coded |
|---|---|---|
| PBC1 | I am confident that I could [perform the behavior] if I wanted to. | No |
| PBC2 (R) | For me to [perform the behavior] is: easy 1 2 3 4 5 6 7 difficult | Yes |
| PBC3 (R) | The decision to [perform the behavior] is beyond my control. | Yes |
| PBC4 | Whether I [perform the behavior] or not is entirely up to me. | No |
Behavioral Intention (INT, 3 items)
| Code | Item wording | Reverse-coded |
|---|---|---|
| INT1 | I expect to [perform the behavior]. | No |
| INT2 | I want to [perform the behavior]. | No |
| INT3 | I intend to [perform the behavior]. | No |
Response scale
7-point scales. Attitude is measured with pairs of opposite adjectives (for example harmful … beneficial); most other constructs use 1 = Strongly disagree … 7 = Strongly agree. Some items put the negative pole on the right to avoid response sets and must be reverse-coded when scoring.
Recoding reverse-coded items: 1–7 scale: new score = 1 + 7 − score = 8 − score. For adjective pairs with the positive pole on the left, reverse so that a high score always means the positive pole.
Licence and permission
The items come from Ajzen's publicly available guidance and the manual by Francis et al. (2004), which may be used for non-commercial research and teaching with acknowledgement of the source, according to the City Research Online repository page.
Sources (APA 7)
- Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50(2), 179–211. https://doi.org/10.1016/0749-5978(91)90020-T
- Ajzen, I. (n.d.). Constructing a theory of planned behavior questionnaire. University of Massachusetts Amherst. https://people.umass.edu/aizen/pdf/tpb.measurement.pdf
- Armitage, C. J., & Conner, M. (2001). Efficacy of the theory of planned behaviour: A meta-analytic review. British Journal of Social Psychology, 40(4), 471–499. https://doi.org/10.1348/014466601164939
- Fishbein, M., & Ajzen, I. (2010). Predicting and changing behavior: The reasoned action approach. Psychology Press.
- Francis, J. J., Eccles, M. P., Johnston, M., Walker, A., Grimshaw, J., Foy, R., Kaner, E. F. S., Smith, L., & Bonetti, D. (2004). Constructing questionnaires based on the theory of planned behaviour: A manual for health services researchers. Centre for Health Services Research, University of Newcastle upon Tyne.
- Henseler, J., Ringle, C. M., & Sarstedt, M. (2015). A new criterion for assessing discriminant validity in variance-based structural equation modeling. Journal of the Academy of Marketing Science, 43(1), 115–135. https://doi.org/10.1007/s11747-014-0403-8
- Kock, N., & Hadaya, P. (2018). Minimum sample size estimation in PLS-SEM: The inverse square root and gamma-exponential methods. Information Systems Journal, 28(1), 227–261. https://doi.org/10.1111/isj.12131
- Ngo, Q.-H., Nguyen, T.-D., & Phan, N.-B. (2025). Exploring green purchasing intentions and behaviours among Vietnamese Generation Z: A perspective from the theory of planned behaviour. PLOS ONE, 20(5), e0323879. https://doi.org/10.1371/journal.pone.0323879
- Tran, Q. A., Nguyen, H. T. T., Bui, T. V., Tran, N. T., Nguyen, N. T., Nguyen, T. T., Nguyen, H. T., & Nguyen, S. H. (2021). Factors associated with the intention to participate in coronavirus disease 2019 frontline prevention activities among nursing students in Vietnam: An application of the theory of planned behavior. Frontiers in Public Health, 9, 699079. https://doi.org/10.3389/fpubh.2021.699079
Vietnamese translation
A Vietnamese translation of every item, with sample-size advice and studies that used the scale, is on the Vietnamese page for this scale.