Exercise 3
Task 1
For this app, the most important usability dimension is Efficiency. This app is only used by Neo and Trinity, therefore they can afford to spend a little extra time figuring out how to set up the system and use it, so learnability is not a big priority. Security is also very important, as they probably don't want outsiders to be able to see details about their expenses, however in this case I would argue it is very difficult to go wrong with security (the spreadsheet provides some amount of privacy, for example). Usability is important, because Neo and Trinity rely on this document to figure out their expenses, therefore it needs to be easy to use.
I find two usability issues with this spreadsheet.
- When one person clears their debt, they need to flush the document. What if they want to track the history of such purchases? The spreadsheet includes a lot of human work which leads up to inevitable human errors. If any issue happens, they might want to look back in the history of spendings. Currently the spreadsheet doesn't enable them to, as it will just take the aggregate of all the purchases in the spreadsheet and the values won't reflect any paid debt. That is, unless you add it in a row (for example under Neo paid for Trinity), which is semantically unintuitive. This is an issue of security, as their system isn't fault-tolerant for human error.
- Editing a spreadsheet whenever you make a purchase is very annoying. Especially with Google Sheets, you need to have the app installed to edit a spreadsheet from your phone (you probably won't have access to your laptop most of the time you use your card). Even then, you need to open the app, create a new row, navigate through the columns, and type out the expense, which takes a good amount of time. Humans get bored, and it doesn't help that the system is not forgiving (you need to track all relevant expenses for it to make sense). This is an issue of efficiency and security, as keeping track of the expense is much harder than spending the money, and not tracking an expense might lead to problems in their finances.