Deciding on minimum performance

Question

I work at a remote site for a multinational company. I am doing a software implementation that is having some major user experience issues due to very poor network performance. Our load times are so bad that we can't roll anything out for fear of complete lack of adoption.

After a long battle we have a project in the works for getting this issue resolved. One thing that came up today was the definition of success for this project. Presently it takes 190 seconds to download a 10MB file through SAP and all stakeholders agree that is unacceptable. A different remote site of similar size and function takes 10.5 seconds to download, all stakeholders agree that is better than acceptable.

There has been some debate on where the lines between acceptable/marginal/unacceptable should be set. How do you decide on what your minimum expectations are for system response? Are there any good external resources for making these decisions?

Answer 1

1. Use the system. As a software developer, you're used to using software, you'll quickly know whether your own system is frustrating to use because you'll start shouting at it. If you're shouting at your own software, it's too slow.

2. Use a competitor's system. Is theirs better? If so, that's your target, but "acceptable" would at the very least be on the same order of magnitude. If theirs takes 2 seconds, yours needs to be in the 1-5 second range, if yours is taking 10 seconds you're way behind.

3. Analyse what the system does, and how often the event will happen. A slow startup once a day is acceptable, slow responses to every click is not.

4. Accept the fact that opinions will differ, and that acceptable is different depending on your use case. I will happily wait a moment for a webpage to open, but if one doesn't appear within 3 seconds for my mother, she will start clicking random buttons. I understand what is happening; she doesn't. The same sometimes applies to your stakeholders.

Answer 2

You don't. You ask your users - either directly "How long do you think this should take?" or by letting then use the system and see whether they complain.

What is acceptable can really differ depending on the context - I have no problem waiting for a bus for 10 seconds, it annoys the life out of me when it takes an app on my mobile 10 seconds to load.

The more frequently used something is, the faster the system is expected to respond.

There are many other variables, but seeing as this is a UX forum - user research should give you answers.