[Question and answer both written in the 'answer' box because the question is long]

We should all be more careful when using social networking sites like Facebook due to the risk of identity theft. Identity thieves operate by getting hold of an individual's home address, which can assist them in perpetrating their fraud. Although the negative consequences of identity theft are sometimes over-stated, it usually leads to a lot of hassle for the victim and sometimes financial consequences.

Which of the following is an assumption of the argument above?

A) Identity thieves want to get information about an individual's home address B) It is possible to obtain home addresses from social networking sites C) For some individuals, the negative consequences of identity theft outweigh the benefits of showing their address on social networking sites D) All social networking sites are targeted by identity thieves E) Fraud based on identity theft necessarily requires an individual's address

The correct answer is B. (in a TSA the test is multiple choice so no explanation is required but I will try and show how you get to that answer)

When analysing arguments it is useful to try and break them up into a series of simple premises and a conclusion (this is called '"formalisation"). This makes things like identifying assumptions much easier. In this case, the 'formalised' argument looks like this:

Premise 1) Identity thieves operate by getting hold of an individuals' home address Premise 2) Having your identity stolen is bad (hassle/financial consequences) Therefore... Conclusion) We should all be more careful when using social networking sites

Notice that these formalised points do NOT come in the order they are presented in the original text (this is something the test writers do A LOT to try and catch people out - be careful).

Once the argument has been 'formalised' it is easy to spot the assumption. You will notice that (as it stands) this formalised argument doesn't really check out. There seems to be a strange jump from Premise 2 to the conclusion - why is it that this information about how identity thieves operate and the negative consequences of identity theft entail that we should be careful on social media? We need to fill in the assumptions in order to make this argument work.

In this case, 'being careful on social media' only logically follows from the preceding premises if there is some link between social media and stealing someones address. Therefore (after considering the multiple choice options) the only answer that fits is B. If you assume (or add as a premise to your formalised argument) that "it is possible to obtain home addresses from social media sites" then the conclusion logically follows from the premises and the conclusion makes sense.