Table 1.

Descriptions of the applied usability tasks

Task	Task description
Task 1	Register as a website user ArboAntwoord.com is a semi-closed website, which means that every user must register the first time he/she wants to login. For every subsequent website visit, a username and password are sufficient to enter. You can reach the website by typing the following link in your web browser: http://www.arboantwoord.com. The assignment is as follows: register yourself as a user.
Task 2	Ask a question to an expert Imagine that you have encountered the following technical problem: you do not know how to ask your question privately or anonymously. What can you do? ArboAntwoord.com provides two possibilities: 1. you can make use of the "help function"; and 2. you can call or e-mail the website moderator. The assignment is twofold: 1. find the "help function" and find out how to ask a question privately or anonymously; and 2. what is the phone number and e-mail address of the website moderator?
Task 3	Solve a technical problem by consulting the help function or the moderator Imagine that you are a hairdresser and often suffer from skin irritation; you have dry, red hands, with scaling and your hands itch. You have noticed these complaints disappear when you have taken some time off work. How can you possibly prevent these complaints in the future? The assignment is as follows: ask this question through submitting it in the corresponding category and subcategory.
Task 4	Search a stored Q&A in the (sub)categories using a direct overview with recent questions or a hyperlink to an overview of all questions in that subcategory It would be inefficient for both the experts and questioners to ask and answer the same question more than once. Therefore, ArboAntwoord.com saves and stores questions and answers and makes them accessible to other users. One way of finding stored questions is by looking in the subcategories. There all "recent questions" asked in this subcategory are presented. We have stored the following question (and answer): "What type of tests should be included in an assessment for an asbestos removal worker?" The assignment is as follows: find this question (and the answer) by searching the corresponding categories.
Task 5	Search a stored Q&A combination (an answer) by using the search function It would be inefficient for both the experts and questioners to ask and answer the same question more than once. Therefore, ArboAntwoord.com saves and stores questions and answers and makes them accessible to other users. Another way of finding stored questions and answers is to make use of a search tool with search terms (such as Google). We stored the following question (and answer): "What happens when an occupational physician reports an occupational disease to the Netherlands Centre for Occupational Diseases (NCOD)?" The assignment is as follows: find this question by using the search function (and search terms).
Task 6	Register as an expert by selecting his/her area of expertise Imagine that you have heard about ArboAntwoord.com and want to register as an expert. The assignment is as follows: register yourself as an expert.
Task 7	Answer a (fictitious) question Earlier today, I have sent you an e-mail with a hypothetical question. This message is the usual e-mail ArboAntwoord.com automatically sends to the expert to whom the questioner asked his question. The assignment is as follows: open this e-mail, make use of the hyperlink that leads to the question and answer it with an "imaginary" answer.
Task 8	Add a supplementary answer to a stored Q&A combination Presumably, experts want to have oversight of the recent questions and answers in their area of expertise. When reading these questions, experts might want to add information to or even correct the answer. For this purpose, ArboAntwoord.com provides the opportunity to give an additional answer or reaction to recently answered questions. We stored the following question (and answer): "What are the risk factors for Occupational Hand Eczema?" The assignment is as follows: give an "imaginary" reaction to this question. You can locate the question through: → main category "work health risks" → subcategory "irritating substances" → (sub)subcategory "water and soap" → The first question in "recent questions".