“我发现我的前任比我现在挣得多 37%！我该怎么跟老板谈谈涨工资的事儿？”

In my opinion, you really can't use your knowledge of your predecessor's salary in your negotiations. The worst move would be to admit in any way that you know how much she made or that you deserve to get bumped up to that level just because she was on that level. I think you need to step back and look at what your job title is, and what the market averages for that salary in your area are paying. You can then argue that you feel a raise is warranted by your exceptional work, and how your performance exceeds normal performance. I.e., say the average for people in your type of job in your area is 70k. You can then argue up from there based on your excellent performance. It's a hard pill to swallow, but you don't deserve $80k just because the person before you made that much. But maybe you deserve $80k because that's the market value for your job in the area you live. Or you deserve it because the going rate is $70k, but you far exceed normal performance for that job. Or maybe you find out the average in your area is $60k. In any rate, any debate on why you deserve a raise needs to center around you, and the going rate/value for your job in your area. It shouldn't be about what somebody else made.

Approach the negotiations from a vague standpoint. You must not let them know that you KNOW what the other person is making under any circumstance.

That will sour your entire relationship with them immediately. It's a secret that they held over you that you've discovered. Letting them know you know will be seen as a betrayal on your part. You weren't meant to see her W2 obviously.

So, then, you must approach all negotiations from a vague, neutral standpoint.

Say you've done research into what other people sharing the same position you have with similar experience/education levels. It may help to actually do this research and then present the results of what you find. Just in case they ask you for evidence, you may want to actually have some. There are websites for this, but if possible, it may help to make contacts with other people doing what you're doing at other companies. That's easier said than done obviously, so it will depend on how serious you are about all of this. It may mean putting in some actual leg work.

Personally I would find that worthwhile, especially given the gap in pay you're talking about, so you'll have to decide for yourself whether you're willing to do what it takes or not. You're always taking a risk when you do this kind of stuff, regardless of how deserved it is or not, so be mindful of that.

Just make sure you do not let them know you know what your colleague is making. That is vitally important. You kinda fucked up there.

Honestly, as a senior manager, I'll tell you this. The information you found out is useless and if anything it's blinding you. You got a job after an interview you think you bombed, but they saw something in you and at a rate that worked for them and honestly it worked for you too. It was what you wanted and what you got and you were happy working at that rate. The fact that you found out someone else gets more than you is irrelevant. It worked for you so you accepted and work, if now it doesn't... hey! The best part of at will employment is you can quit anytime. Now, instead, use your reviews as a time to tell them everything you're doing to help improve the company and improve processes, etc. Now, during your review.... tell them and ask them, what their expectations are, what your expectations are, where you want to be, and what you need to do to get their. If you guys come up with a plan or etc... great! If not... be Frank and thankful and then start looking for another job that does meet your requirements.

Don't be bitter or angry that your predecessor got more. Be happy that you got what you wanted or that there is room for you to grow and improve your financial status... you're growing and developing your career, if nothing else: control your emotions and don't loose focus. Honestly, it sounds like your family is growing and you're building your career. Don't settle, ever! But... take the win and build on it. You are developing your career. Be smart and kill it! You sound like you will...

2 things, first what any negative emotions your feeling can just be called jealousy or envy. Can’t remember which one. Don’t take offense to that, it’s a normal response but if your content with your situation and then only feel negative emotions once you hear about someone’s situation that’s the definition of the correct one of those words. They aren’t fun emotions but it’s helpful to know what it is to help you make wise choices moving forward.

I’m also in a similar position to your hiring manager as we are possibly promoting an untested person into a bigger role so I may be able to give you insight as what they are thinking on the other side. First there is no way we are promoting her to the same salary level for a few reasons. She is an unknown in this position and we aren’t going to pay the same when we don’t know what quality we will get. The other person got to their rate after years of quality proformance, taking on new tasks and consistency. She may outperform the previous person but we aren’t going to pay assuming that.

It’s also a lot harder to lower salaries than the other way around so if she underperforms for awhile we don’t have to fire her because she is getting overpaid and this will give her time to learn and improve. We also pay for appropriate value in the meantime.

It’s also easier to keep her happy as people tend to be satisfied by how their situation has changed not how it is. This means if we start her out lower we have more room to give raises and keep her job satisfaction high. If we start out at a high rate and she has good proformance it’s hard to keep her happy unless we start over paying for the position, because the typical person just sees that they are preforming well and that they aren’t getting salary increases, which then leads to employee dissatisfaction when in reality we just started paying at our top dollar.

Lastly, the blunt truth is that companies are at odds with their employees in this regard and I hate this part of how it all works. It’s to the companies benefits to pay you less if they can get away with it and to do so for as long as they can (and not lose you or your productivity.) business is very competitive and if your not finding any and all competitive edges you can, the business could be short lived if you don’t work to create and hold onto them as they can be fickle and challenging. if your employer has a competitive advantage by paying you less they aren’t going to want to give it up unless they have to.