Could a seemingly random sum of money help voters make their decision in the Scottish independence referendum?
Since 2011, the authors of a survey on Scottish social attitudes have been asking the same key questions based around the figure of £500.
If under independence you were £500 better off would you say "yes" in the referendum and if you were £500 worse off would you say "no" in the referendum?
For ScotCen Social Research, which conducts the annual survey, the findings are clear.
In the 2013 report - involving the interviewing of 1,497 people between June and October - the suggestion was......
- 52% would support independence, and 30% would oppose it if £500 a year better off
- 15% would support independence, and 72% would oppose it if £500 a year worse off
In the 2011 report - when 1,197 people participated - the suggestion was....
- 65% would support independence, and 24% would oppose it if £500 a year better off
- 21% would support independence, and 66% would oppose it if £500 a year worse off
So, could £500 be the referendum deal breaker? And if so, why?
Prof John Curtice, research consultant with ScotCen Social Research, said he and his team were the first to use the figure. But was it based on hard facts or totally random?
He explained: "We first asked the question in 2011 as we sought to better understand the trade-offs that the public were making in forming their view of Scottish independence.
"It was designed to assess how much economic considerations would influence support for independence.
"The £500 figure was a best guess for an amount of money big enough to have impact on a person's material well-being, symbolic of an improvement in an individual's standard of living, but not so large as to completely override everything else."
Since Prof Curtice settled on using £500 for his research, other pollsters have followed suit.
ICM's September 2013 poll showed that if people could be convinced an independent Scotland would make you richer by the amount of £500, 56% would vote "yes" and 44% would vote "no".
The promise of a £500 deficit on the other hand produced a "yes" vote of 22% and a 78% "no" vote.
Panelbase has used the figure twice - in February 2012 and November 2013 - but with a different question entirely.
Instead of offering its sample the £500 figure as a guarantee, it asked participants: "In terms of your personal circumstances which of these statements most closely reflects your view?" It then gave them the following answers to choose from:
- I believe I would be at least £500 better off per year in an independent Scotland (13% in February 2012, 15% in November 2013).
- I believe an independent Scotland would make little difference to my financial circumstances (40% in 2012, 26% in 2013).
- I believe I would be at least £500 worse off per year in an independent Scotland (20% in 2012, 34% in 2013).
- Don't know (27% in 2012, 25% in 2013).
Panelbase Managing Director Ivor Knox said he used the ScotCen Social Research figure of £500 "for consistency" reasons.
Regardless of what sum of money you go for, Prof Curtice believes research consistently shows how important an individual's personal finances are when it comes to making a choice in the independence referendum debate.
He believed people seemed to be saying: "You know what, I might be able and willing to vote for independence,
"I might be willing to leave my Britishness aside if I think I am going to be better off, but equally, conversely, a lot of people who feel strongly Scottish say, look I'm not going to do it unless you can convince me I am going to be better off.
"So, that in the end is why this issue of economy kicks in. Voters need more than just their sense of identity to decide how they are going to vote."