Gulf of Execution and Evaluation

The Gulf of Execution: well, I'm supposed to kick or something, but where and how? How fast? Or do I kick or just wave my foot? And the Gulf of Evaluation: well, I did it, and nothing happened. Now what am I supposed to do? Really good example of bad design. Two sources of difficulty when using a product are due to the lack of discoverability and feedback: knowing what to do, then wondering what happened. 

These two difficulties result from the huge Gulf between a person's goal and the means of achieving them. This is called the Gulf of Execution. There's also the Gulf between assessing the state of the world and trying to determine if that state matches the initial goal. And this is called the Gulf of Evaluation. Figuring out what actions are possible during the Gulf of Execution is all about discoverability, and knowing what just happened during the Gulf of Evaluation is about feedback. Ever buy a new product and then not know how to work it? Well, likely because it lacks discoverability. Ever stand at an elevator or a pedestrian traffic light pushing the button but not knowing if the system noticed, so you push over and over again? That's because of a lack of feedback. 

The rule of the designer is to help people bridge the two Gulfs, making the possible actions discoverable and providing feedback along the way.  I thought one of our coffee machines was broken because it didn't work immediately upon me pushing a specific button. What I eventually learned from a colleague was that the coffee machine needed time to warm up prior to processing my request. This important step wasn't part of my conceptual model, hence the misunderstanding. 

The coffee machine failed me by not providing appropriate feedback. It should have let me know that it had received my request and was taking time to warm up. We'll cover the important topic of feedback more soon. Crossing the Gulf of Execution and the Gulf of Evaluation involves users asking themselves a series of questions. For each of the seven questions, indicate whether the question occurs at the user's goal, the action done to the world, the Gulf of Execution, or the Gulf of Evaluation. 'What do I want to accomplish?' or 'What is my goal?' 'What are my alternatives?' 'What can I do now?' and 'How do I do it?' occur at the Gulf of Execution, when users are trying to figure out how to execute. 'Have I accomplished my goal?' 'What does it mean?' and 'What happened?' are questions users ask during the Gulf of Evaluation, in order to determine what happened in response to an action taken. No question is asked at the world; the world is simply where the action occurred. Good designers empathize with the people they're designing for.  Your job is to make sure that the people using the product can always find the answers.