As the SNP attempted to give 16 year olds a vote in the EU referendum last night, I had a (slightly arcane) conversation in the office about whether, if we granted 16 year olds the vote in all general elections, this would give them greater or lesser influence over the course of their lifetimes.
Lowering the voting age has two effects on this. Firstly, and most obviously, it means that you're likely to vote in a general election more times - meaning more influence. But secondly, it means that the electorate is larger - so each individual vote you cast is worth less. Which of these two effects are larger?
We can do a bit of maths to try and work it out.
Let's define your "voting power" in each election as being 1 divided by the number of people voting in your constituency (on average about 47,000 in the last election). I've chosen constituencies because, of course, under our electoral system, you can only influence the fortunes of the MP in your constituency and not all of the others.
Over your lifetime, you will on average vote in 12.7 elections - that's assuming you have the average life expectancy of 82, and there are elections every 5 years as dictated by the fixed term parliament act. So we can calculate your "lifetime voting power" as being 1/47000 voting power in each election times 12.7 elections. Which at present gives us a number of 0.000269. Isn't democracy wonderful.
If the voting age is lowered to 16, there are 2.5% more people eligible to vote (according to census figures). So the number of voters in each constituency becomes about 48,000. But you get to vote in more elections - 13.1 on average! This gives us a "lifetime voting power" of 0.000271.
So, on this metric, you will have 0.6% more influence over the democratic process over the course of your lifetime under votes at 16. Although, of course, your influence relative to other voters will be exactly the same as everybody will be operating under the same rules.
But there is a final impact of this possible change in the electorate that's worth a thought. Your overall voting power is higher, but only because you get to vote in 0.4 more elections as a result of being able to do so when you're young. The votes you cast when you are older are diluted by younger voters - so effectively this is a transfer of influence from your older self to your younger self.
Which means votes at 16, at least on this measure, boils down to this question: are you willing to have more power over governments over the course of your lifetime if it means taking power away from your 80 year old self and giving it to your 16 year old self?