People who've read my (rather sparse, I know) blog know I'm hugely fond of quantifying ... everything (how fond am I of quantifying things? Turns out I'm 73.8% more likely to quantify unquantifiable qualities than the median of the population!). At some point in my career, somewhere 10-15 years ago, I came up with a scale to assess how happily 'sticky' my current workplace is, also known as "how likely am I to leave right now?" (or, to follow in Rands' metaphor, "how strong are my shields right now?"). Being a 0-5 scale, this has some nice alignment with ratings in my company's systems, but this is but an accident.
5: I'm super-happy at my job. My best friend could offer me a fantastic job and I'd basically go "meh, call me in a year, maybe I'll be ready then"
4: I'm very happy at my job. I'm probably unlikely to entertain job offers from strangers. If a friend contacted me and asked me to look at a particular position, I might do that as a favor, but not because I'm interested in looking elsewhere (that said, at least one job change in my career started off like this -- Andrew Voltmer asked me to interview at Macromedia, and despite being very happy at my current place I went basically as a good will gesture. After having my butt handed to me by Marc Powell and Eric Thompson in the interview, I remember leaving Macromedia's offices sure of only two things: 1. I didn't get the job; 2. If I'm wrong about (1) I really wanted the job).
3: Sure, I'm willing to talk to people if there's some sort of reasonable position that might be interesting. I might or might not be actively looking, but if I'm actively looking it's at the "talk to friends and see what's out there" level, not the "actively submitting resumes through automated candidate tracking systems" level.
2: Get me out of here! I'm actively looking for a different position and I'm looking for ... pretty much anything reasonable. I'd like to leave here soon, damn it, and I'm actively, materially, dissatisfied.
1: Here's my resignation, with some reasonable advance notice (2-4 weeks). I don't yet have a job, but I need to leave. I'll figure out the details and where I'm going next later.
0: Here's my resignation. It's effective immediately. Don't worry about my stuff, it's already in my car. This was my last day of work. We're probably not going to speak with each other again.
No notice? Really?
I'll admit that I've never gotten to 0 (in fact, I've not gone below 3). I reserve 0, hypothetically, to situations where I've discovered that if I remain at my company I'll be party to conduct that is either illegal or materially inconsistent with my principles and ethics.
But ... Why?
Why quantify this? Aside for my desire to quantify most things, it's also a reasonable framework for figuring out how interested I am in the various random LinkedIn solicitations I get. If I'm at 5, or 4, I can save people some time and effort and not engage. If I'm below 4 ... there might be some value for discussions. It's also worth being aware when the score changes, and figure out (especially if it goes down) what the reasons for the downgrade are (and whether or not I want to do something about them).
 I'm also about 68.2% more likely to make up numbers when I can't find them.