At interviews you are sometimes expected to know where you want to be career-wise in 20 years. In a world where things change very quickly it’s very unlikely you know where you will be next year!
However, it is key to have career goals be they short, medium or long term. Children growing up now should probably consider which job first rather than what they want to be. It’s more acceptable in 2014 to have switched jobs or even careers and this acceptance is only set to increase in my opinion. Interviewers’ themselves may only have had one job or perhaps only ever worked at one firm. Are they the right people to interview others in an age where job hopping is the norm and not necessarily a reason to think negatively of someone that skills-wise fits the job spec?
At interview focus on what your goals are, this will still impress the interviewers and prompt further discussion. It’s ok to say ” I am not sure where I see myself in 20 years but these are my short and medium term objectives”. Presented in the right way and in the context of the job spec for which you have applied, this should demonstrate that you are someone that knows themself very well and you are a positive thinker, upbeat and good to have around the office (even though you are not sure what you will be doing in 20 years time)!
For more examples of interview questions please see http://www.bcllegal.com/interview-tips-and-advice