Hierarchical Task Analysis (HTA)

HTA technique aims to provide a better understanding of a task. It describes the task in term of its sub-tasks. It has many uses, one of which is interaction design. This blogpost will do the HTA for the following tasks:

•  Borrowing a book from NCL library through self-service machine
•  Making a cub of Macchiato  at home using Espresso machine

Borrowing a book from NCL library through the self-service machine

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There should be some dark lines under some sub-tasks but when I drew them the picture became little cluttered so I uploaded them without those lines that clarify which task does not branch to more subtasks.

My experience doing this initially was a bit awkward because it perhaps the first time I thought in such manner of usual things. Thinking about what tasks imply more steps, deciding the start point and the endpoint for the task could be arguable stuff. Some steps which have multiple ways to do can confuse. So, I decided to pick only one route which is my personal way to do that as it shown above. However, in general, I believe, it is a nice thing to start of thinking in that manner, this approach may help detect some problems that hidden within complicated systems.

Making a cub of Macchiato  at home using an Espresso machine

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I have been making this kind of coffee using those steps for a long time.Thus, I was confident that this task would be easy than the one before, but I realised that describing the task is harder than making the coffee. There are many ways of doing coffee drinks and this one only describes the way I like it. Basically, the main factors that affect making Espresso-based coffee in my opinion: the type of coffee, the type of milk, the heat and the amount of milk. Anyway, I am sure the HTA for this task can be refined more if we described from the perspective of the objective which is in summary Macchiato drink should have a little foamy milk on top of espresso. Also there are some considerations regarding the machine itself. I have made these steps which can be work on my machine. Other users should follow the instructions that come with their Espresso machine to avoid hurt themselves by the hot milk or the high pressure  of steam and to make a proper Macchiato.