What it looks like
An example from Psychology.
Milgram (1963) found that 26 of his 40 participants went on to the highest shock level, 450 volts. The module textbook explains that this shows ordinary people will obey orders to harm others.
Milgram (1963) found that 26 of his 40 participants went on to the highest shock level, 450 volts. Burger’s (2009) partial replication, stopped at 150 volts for ethical reasons, found obedience rates only slightly lower than Milgram’s. But Haslam and Reicher (2012) argue that participants were not blindly obeying: they went on when they identified with the experimenter and believed in the research.
Why markers write it
A narrow source base makes your argument fragile: if your one source is dated, partial or wrong, so is your essay. Range also shows the marker you know the field — that there are replications, critiques and newer findings beyond the textbook. Most UK marking criteria expect independent reading beyond lecture material for the upper bands.
How to fix it in your next essay
- 1Use the textbook as a mapFollow its references to the original studies, then read and cite those instead of the summary.
- 2Mix the kinds of sourceAim for original studies, review articles and academic books, and include recent work, not only the classics.
- 3Look for the source that disagreesFor each key claim, search for a critique or a replication. Google Scholar’s “Cited by” link is a quick way in.
How much it costs
In most UK marking schemes, reading feeds into the marks for evidence and argument, so a narrow range usually costs marks across several criteria and can hold an otherwise sound essay in the 2:2 range.
Other ways markers say it
- “Narrow reading”
- “Needs a wider range of sources”
- “Over-reliant on one source”
- “Too reliant on the textbook”
- “More academic sources needed”
Often written alongside
Common questions
- Can I use websites?
- Some. Official bodies and reputable organisations can be fine for data or policy, but they shouldn’t replace academic sources for your main argument.
- Are lecture slides a source?
- Usually not one to cite. Use them to find the original reading, then cite that.
- Are older sources a problem?
- Not if they’re classics. Milgram (1963) is still essential, but pair classic studies with what’s been found since.