Evaluation Assignment

This first assignment of the course consists of the evaluation of the (user interface aspects of the) university's coffee vending machines. The evaluation is done by trying the following scenario (and experiment):

You arrive at the coffee vending machine with an English guest. Your guest (to be served first because that's polite) wants slightly weakened black coffee with a lot of suger. You on the other hand like strong coffee with a bit of milk.
TUE: In your wallet you only have one coin of one guilder. (You know that this is enough for two coffees at the TUE.) You want to show your guest the user-interface in English but before actually ordering the coffee your guest asks you to switch back to Dutch so you can order the coffee in your own language.
UIA: In your wallet you only have two coins of twenty francs. You know that twenty francs is not enough for two coffees so you insert both coins before ordering the first coffee.
TUE and UIA: When your guest and you both have their coffee you try to get the vending machine to give back some change, which you put back in your wallet.

In principle you should follow this scenario exactly. However, when acting it out you are allowed to actually select the settings for coffee you like (possibly adding more or less milk and sugar) and you are not required to drink the coffee if you don't like it. Also, select one particular vending machine for the entire assignment, and write down which machine you used. Not all coffee vending machines use the same version of the user-interface software, so there may be differences in the behavior.

You should first get a good idea of how the coffee vending machines work. After that you must perform (and report on) the following activities:

  1. A cognitive walkthrough;
  2. A formal and a back-of-the-envelope action analysis; do not forget to take into account the actual time it takes the machine to brew the coffee!
  3. A thinking aloud experiment, during which you record on paper what the user is thinking (aloud), what is happening, and how long the whole procedure takes.

The experiment requires a team of three people: a subject, an observer, and an "expert" who is there to help out if really necessary. (The expert can also act as the English visitor.) Therefore this assignment is performed in groups of three students.