Researching Usability

Roundup 26th Feb: The Three P’s in a Nutshell

Posted on: February 26, 2010

Power, Perception and Performance (P3)

As part of the ongoing literature review I’ve been researching some of the theoretical models created or adapted to evaluate information systems. Over the last couple of weeks I’ve been blogging about the Technology Acceptance Model (TAM) which has been used by researchers to show its effectiveness at determining user acceptance of specific systems. The paper by Andrew Dillon and Michael Morris, Power, Perception and Performance: From Usability Engineering to Technology Acceptance with the P3 Model of User Response (1999), reveals limitations of the framework in the context of a usability engineering perspective. It is not clear how well TAM predicts usage when testing prototypes as research using TAM to date has involved the testing of complete systems. If the functionality is limited or incomplete how adequately can participants rate its usefulness? Additionally, they are less likely to be able to rate the system’s ease of use if the interface features have not all been designed yet.

The data collection method was also critiqued because it relies on self-ratings from the participants. Studies have shown that user’s ratings change with repeated exposure to a system over time and that it may shift independently of the usability of the interface. This also relates to last week’s blog which suggested that what users say and what they do are not always the same. Self-ratings provide quantitive feedback from users but ideally this data should be gathered in addition to observation which is conducted at regular intervals to reflect any system self-efficacy.

The issues raised certainly do provide a strong argument against using TAM if you are a designer looking for issues to fix. TAM will tell you if a system is likely to be accepted by users but may not provide insight into why. It is more beneficial to IS professionals or managers who want to know if a system is likely to be used, for example when considering the procurement of a new IS.

The P3 model developed by Dillon and Morris uses three aspects (power, perception, and performance) to assess a user’s ability to use a system. A system’s power indicates its potential to serve the user’s tasks. Perception and performance measures the user’s behavioural reactions. Dillon and Morris believe that the P3 model predicts the capability to use a system through effectiveness and efficiency while TAM reveals the perception of the system. Consequently these different constructs make them independent entities which should not be compared: “The P3 model is an attempt at providing a unified model of use that supports both the process of design and clarifies the relationship between usability and acceptability.”

Useful program: Nutshell Mail

I was alerted to this wonderfully simple tool from Mike Coulter during his Ambition presentation, Listening Online. Trying it out is the simplest thing and takes less than a minute to set up. The website describes the program as follows:

NutshellMail takes copies of all your latest updates in your social networking and email accounts and places them in a snapshot email.

It’s a great way to manage multiple accounts and could be useful for those of you who either can’t access your social media accounts throughout the day or have so many people in your network that you find it difficult to monitor your feeds effectively. Last week I blogged about the limited usefulness of Twitter Groups because of the way they are accessed. Well I might be eating my words now because Nutshell Mail gives you the most recent results from your groups in each email along with any other accounts you choose to connect, including LinkedIn, Facebook and MySpace. You can also schedule the emails to arrive at a time that best suits you. That way its less likely to get lost amongst all the emails that wait you every morning! Although another piece of mail in your inbox might not sound like the ideal solution for some people, I’m willing to give it a try to see if it does make life a little easier.

Remote Research by Nate Bolt and Tony Tulathimutte

I was alerted to a competition this week in which UX Booth were giving away three copies of the book, Remote Research. As I’ve conducted some remote studies myself, this was a topic that interested me. I thought I would try my luck and low and behold I actually won a copy which I have already received! Books by the publisher, Rosenfeld Media are always informative – I already own Web Form Design by Luke Wroblewski and Card Sorting by Donna Spencer. Looking through the contents it looks like this book continue this trend. Most notable is the chapter entitled ‘The Challenges of Remote Testing’. The debate of remote testing versus direct testing has been ongoing for a while and looks set to continue. In this chapter some of the possible pitfalls are discussed which will hopefully help users make informed decisions on how they conduct user research and select the best tools to meet their needs. I look forward to reading this book, the simple design of Rosenfeld books makes them quick and easy to digest. Due to interest, I hope to write my own review here once I’ve finished it.

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1 Response to "Roundup 26th Feb: The Three P’s in a Nutshell"

Thanks for the recent discussions on evaluation frameworks. This highlights the manifold and complex aspects involved in user studies. It is difficult to pin down and gain knowledge of (local) use contexts. Usability testing appears to be more straight forward in comparison!

Is P3 therefore a closer relative to the Interactive Triptych Framework given the performance aspect which is lacking in the TAM?

Interesting comparison between the evaluation of prototypes and completed systems. I think the efficacy of an approach that is capable of measuring user acceptance of *ideas* is important particularly in user-centred design. Instead of a summative and fully fledge evaluation (uncovering issues difficult to address in late stages of JISC projects), small-scale, informal and formative assessments of UI mockups, along with working prototypes are perhaps more effective tools in steering system developments.

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