Determining how much closer a sequence is to another series?

I am supposed to make a game in which a range of numbers starting from 1 are scattered across the screen and the player has to click them in series. Somewhat like this but much less range,

You have to click them like 1, 2, 3, 4...

What I need to know is how to determine the score. The time to click be $t$ seconds,

Now comes determining how much closer the clicked numbers were to the original sequence [1, 2, 3..]. The fact that I had payed some little attention in my statistics classes, I thought that the answer might be correlation but the glitch is, if the numbers are clicked in reverse Coefficient of correlation will be -1. If I would take the absolute value it becomes 1 which is the same if they were clicked in perfect sequence.

I can add some constant factor to the coefficient.

$$\frac{\sigma+5} t *100$$

But I do not think it is the best way.

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 Just make a score that is equal to the sum of the absolute differences between the clicked sequence and the actual sequence. – Raskolnikov Jul 6 '12 at 5:38