An industrial engineer hired by a manufacturing firm will go into some sort of optimization, usually. There’s no generic answer for what IE’s do other than that, so here are some examples:
For example, you might be hired by an airline to look at how to price a flight in order to maximize revenue. Should you have 20 first class seats or 10? Should you put deeply discounted seats on Priceline to increase sales, and if so, how discounted? Should you use a different size plane?
As another example, you might work for a manufacturing firm benchmarking a manufacturing process. How long should it take to assemble a computer? Where are the bottlenecks? Should you add a second line for a particular process?
As another example, you might work in transportation and logistics optimization. Should we fly the parts from China or should we ship it? If we use trucks, what route should the truck take? Should we relocate our plant to China and just ship finished goods rather than raw materials?
Yet another example is working for the Red Cross. Given that the Red Cross has a large amount of resources to deal with disaster relief, and no one knows where the next disaster will be located, how should the Red Cross store their goods? Should they have one central warehouse with planes that can get resources to an area fast? Should they have some regional warehouses spread throughout the world? And if so, where?
Another example is working at a hospital. Patients come in and are treated, but should they be treated first come, first served? Most critical to least critical? Most doctor time to least doctor time? Given that a doctor costs twice as much as a nurse, should you have more nurses and less doctors or more doctors and less nurses? How many OR’s should you have? Non-critical patient beds? ICU beds?
You could also work in warehousing. Given that you have a large warehouse, what’s the optimal way to store material inside of the warehouse to decrease the amount of time it takes a worker to pick items for shipment? How many out-bound shipment doors? How many in-bound? Should you use a few large trucks for delivery or several smaller ones?
Then there’s consulting. A private equity firm wants to buy this small company. Should they do it? Is the small company’s operation setup properly and is there anything quick that the PE firm can do to raise revenue quickly?
Eventually, my goal is to go into the business world or finance and be in management positions. So would it be better to do Industrial Engineering + MBA or Economics/Business + MBA?
If you want to go into business (and I mean high 6-figure / 7-figure salary type of business), you need to work backwards:
- You need to go to a top MBA program. Lower tier MBA programs are worthless. You need a Wharton, Harvard, Stanford, MIT-Sloan, etc. on your resume.
- How do you get into those top programs? Hint: it's not your grades. A 4.0 GPA with a 700+ GMAT doesn't guarantee you admission. Instead, what you need is the right work experience. What's the "right" work experience? You need to work for a company that traditionally places into those MBA programs (has connections) and that can introduce you to people that make important decisions: C-level managers at Fortune 500 companies. When the Chief Operating Officer of GE writes you a letter of recommendation to Harvard, you're in.
- How do I get the "right" experience? Work for one of the big consulting, banking, or private venture companies. If Bain or McKinsey hire you as an undergraduate, their entire goal is to get you into Harvard then rehire you at graduation (clients won't pay them much for a Georgia Tech BS, but will pay them a ton for a Harvard MBA). To get you into those schools they will put you in high profile positions where you can meet important people. Walmart is considering purchasing Target? Guess what - you're the guy standing in front of Walmart's CEO talking about the operational benefits that Walmart can bring to Target. When the acquisition happens and is a success, you now have on your resume that you assisted in a $40 billion merger and Mike Duke (the CEO of Walmart and GT IE graduate) puts in a personal call to get you a full scholarship and admission to Harvard Business.
- How do I get a job with one of those big companies? You go to a school that those companies target. Harvard, Stanford, MIT, Georgia Tech, UNC, UVA, Duke, etc. Those companies target top schools only and target the top students in those schools (3.5+ GPA's, good leadership and work experience). Is going to UGA and earning a 4.0 going to help you? No. Because the companies that can get you to the next level do not recruit at UGA. If it was purely a GPA game, everyone would go to West Georgia and graduate with a 4.0. Is going to GT and earning a 2.8 going to help you? No. You've knocked yourself out of contention for a top job. So if you want to play this game, you need to go to a top school and earn a top GPA.
There are obviously other ways to get into top programs - some people luck in (they get hired into a typical office position and make friends with some powerful people), some people find alternate routes (start up the next Facebook and make billions and you can go to any college you want - although the appeal of an MBA at that point probably isn’t that great), some people work their way in through a professor (find a professor at a top program, show interest in his research, provide him with some data from your company, and sometimes you can use his support to leverage admission). But the above is the best “recipe” for success.