Writing a 30 mark source essayWatch
Guide to assessment (hope this is your spec), includes points for 30 markers: https://www.ocr.org.uk/Images/373399...1-2-and-3-.pdf
A number of graded 30 mark answers to a question (highest is 28/30): https://www.ocr.org.uk/Images/514700...commentary.pdf
Hope these help you understand the structure required.
The source question is largely based off provenance where you analyse the value of the sources, as well as analysis of the content of the sources. Although it's possible to write the question thematically, various examiners' reports have said that this approach often becomes muddled, and that it's easier to achieve the top band of marks by tackling the sources one by one. The difficulty with this is managing to finish, as you have to discuss all 4 sources in order to do well, so you'll want to work out how long to spend on each in the exam!
Personally, I don't tend to write introductions to the 30 marker beyond a sentence or two which summarises which sources I think are more credible, and my overall answer to the question. Some schools near mine advised people to write 3-4 sentence intros, but I think that it's about preference, so quality over quantity with the into!
In each of my 4 body paragraphs, I like to choose a few elements of the source's content (such as the claims of the writer, ideas about certain events, etc), and a few elements of provenance to discuss. I will always use quotes to back up my claims about the source, however, these should not be analysed like they are in English - it's more of a comparison to the objective facts you have about events.
With this question, however, it is often provenance which catches people out. Provenance is when you say how much worth a source has based on facts. However, you should try to make your provenance as specific as possible to the context of the question. For example, if you analyse the provenance of my response, ideas that you discuss might be that
a - I did OCR history -> I know what the specific question requires, and so can credibly tell you how the question works.
b - I got an A* mark in my last 30 marker -> I can do the 30 marker, so my response is fairly creible.
c - I haven't done exams and so have no final grade to prove my ability in history -> My answer may lose some credibility.
d - I haven't done history for 3 months at this point. -> I haven't practiced these questions recently.
Having discussed different elements which impact the provenance, it's then helpful to conclude the extent to which you believe the source is credible, perhaps by saying that (for example) point C becomes irrelevant compared to points a and b, making the source credible to a large extent. My history teacher also always said that provenance, where possible, should focus on things you wouldn't know if you hadn't studied the topic. For example, it's all very well saying that a source has strong credibility because it's a diary entry and so reflects what the writer actually thinks, but you could say that without studying the topic. It would be better to say that the diary was edited and published after XYZ happened, meaning that...
How much you write in these paragraphs will depend on you, but you will need provenance and normal analysis of the different ideas within each body paragraph. You should also remember to keep refering to the quesiton throughout.
The conclusion should be the product of your evaluation of the different sources. Unlike the 20 marker, you're not concluding what you think - you're concluding what the sources think. Therefore, you need to specify what each of the sources claim, and why certain sources are more credible than others. Here it's particularly necessary to focus on the question, so I for one would always conclude the essay by rephrasing the question into something like 'Therefore, the sources conclude to a large extent that...ABC'.
As always, I will say that different schools and teachers mght teach this question in different ways, and that the advice I was given will not necessarily be exactly the same as the advice your teachers would give. Howeve, I hope this clarifys things at least a little bit, and feel free to ask if you have any other questions. (I did Churchill for my source question).