# How did Lacie's rating fall to a Zero?

In the Black Mirror Episode "Nosedive (S3,E1)", towards the end, Lacie's rating falls below 1 and goes to a '0', thereby sending her to a jail of sorts.

In the app that they use to rate each other, the minimum rating you could give someone would be 1 star highest being 5. So a person could go to 1 (but to be honest even a perfect one is impossible since she always had been a 4.2, mathematically she would always be a 1.00000something even if she got all 1s in a row)

My question is how did she fall to below 1? Since the lowest rating one could get is 1, how did she end up with a 0.something? Did I miss something?

• Is it mentioned in the episode that you can't give someone a "0" Star rating? Commented Nov 12, 2018 at 20:08
• In the last scenes (and even from the beginning the lowest is a 1 star), the people at the wedding keep giving her 1 star.
– Anu7
Commented Nov 13, 2018 at 7:12
• This is an important detail to note regarding many "5 star" rating systems (like Amazon). Intuitively it seems like it would be a scale of 0% to 100% (0-5 stars) but actually it is a scale of 20% to 100% (1 to 5 stars). The overall rating is automatically given a 20% boost. This makes the product look better. Commented Nov 29, 2018 at 15:17

Because she was on double damage due to her punishment from airport security:

So her rating was getting double the damage for 24 hours and when she reaches the wedding her rating was already 1.1:

So that's how her rating was going below 1 and last time we see it it was not zero but 0.7:

And she ends up in jail for wrecking the wedding. She got uninvited when she was on the way with 2 point something rating.

• If Double Damage means that every rating counts twice, then it wouldn't explain how she can get below "1" (assuming that "1" is the lowest you can give someone). But if it actually means halfing your rating, then it would (e.g. a "1" Star rating turning into a "0.5"). Commented Nov 12, 2018 at 20:15
• @Oliver_C I am sure it means 0.5 because all guest were giving he 1 star and her rating started falling below 1 and she was on double damage for negative rating Commented Nov 13, 2018 at 2:23
• Oh another doubt cleared thank you ! I was wondering if she was in jail for falling to 0.7. Its cuz she wrecked the wedding. And also i still don't get the math of this because IRL, i'm only ending up with 1 as least. So I'll take it as a software thingy. Appreciate the detailed answer though, i forgot about the double down voting ! :)
– Anu7
Commented Nov 13, 2018 at 8:57
• Still seems weird to me that double damage would allow the rating to go below 1, if people could only rate 1 at the lowest. The way the system is described, it seems like it would give double the weight to the negative voting during double damage; but that should still only make them approach 1 faster. It shouldn't make the average drop below the scores themselves. It would still require votes of 0, or this entire system has to operate on something that isn't averages.
– JMac
Commented Nov 14, 2018 at 15:21
• I have just rewatched some of the scenes and just as the first screenshot here shows, the airport security guy does indeed say: "...all downvotes are subject to a times two multiplier...". - And in the second screenshot, the small print under Double Damage also says: "All negative rankings count 2x". - So Double Damage can't be the explanation (btw, at the wedding her rating actually goes down to 0.6). Commented Nov 14, 2018 at 18:36

While the total ranking is measured on a 0 to 5 star scale the scores that can be given must use a range of at least -1 to 5. Mathematically it's the only way her ranking could dip below 1.x and eventually dive to 0.

To flesh out the episode's parlance: negative ranking must be any score that is given that is below the user's current average (and thus would bring down their rank). A downvote (a term that is only used once after Lacie is given the "double damage" penalty) must be a special (and particularly cruel) rating type that is equal to -1.