 We need tools to better understand the situations in which our hearing aid users are struggling. So we have taken COSI, the Client Oriented Scale of Improvement, out into the field and are continuously reporting on people's experiences while they are in the situation and simultaneously locking the environment that is around them. We have used the following procedure. First, the client comes into the clinic for their initial fit. The client lists situations where they have difficulty hearing. For example, a person can highlight that the sound is distorted when they play the piano. An app is downloaded to the client's phone so they can evaluate the situations momentarily. So when the person is in the difficult situation, they are opening their app and filling out on their experiences and simultaneously we are locking the acoustic environment around the person. Then they fill out in what environment they find themselves in, what their intent is in the situation, how difficult it is to hear, and how important the situation is and how often the situation happens. And then finally, whether their hearing aid helped them in the situation. Four to six weeks after the hearing aid fitting, the client comes back to the clinic for a follow-up visit. The client evaluates whether there has been an improvement of their hearing in the different situations. If needed, the hearing aids are fine-tuned based on the client's feedback. A questionnaire will also be filled out by the client, evaluating how they have experienced the method of giving immediate feedback on their listening situations in the field. For example, they are asked to rate whether they have felt that they had an influence on their hearing aid fitting. Now the client is again sent home and will evaluate on their experiences using the app. Six months after the initial hearing aid fitting, the client will fill out the same questionnaire that they did at the follow-up visit. And the data collection will be ended. We hope that this detailed mapping of difficult situations can provide more input for future interventions and hearing aid processing strategies.