As Charles sort of suggested, there's probably some sort of economics-based differential equations that could be used to model return vs risk vs time in various investment activities.While it probably wouldn't be useful in real life (not sure you could tune the inputs well-enough to be meaningful), you could probably play around with various inputs to get a feeling for their sensitivities to one another.If I were smarter, I'd probably be able to apply some of the utility modeling work I used to do as a poker player to real estate investing...Which actually reminds me that I've been meaning to start a really geek thread on a related subject...a bit off the topic (or maybe not), but if you've studied card counting in blackjack or were ever a geek poker player, you may be familiar with the Kelly Criterion...I've recently started thinking about whether there is a way to apply the concept to portfolio real estate investing:http://en.wikipedia.org/wiki/Kelly_criterion

I used to have a Blackjack and it was actually a very good phone!

I spent $9.95 on Robert Allen's, "Nothing Down", (when it was first published ;-), $50.00 for a used cassette tape series from Tom Hopkins on "How To Master the Art of Selling"$100 for a used Carlton Sheets Audio CD series (I forget the title)$19.95 for "The Pre-foreclosure Property Investor's Kit" by Lucier, $18.95 for "Making Big Money Investing in Foreclosures" by Conti & Finkel, spent multi-thousands of dollars in advertising doing pre-foreclosures and fix & flips and making a cool mil in profit, in addition $1,599 for John Burley's (2) 3 day live sessions (6 days total) on "Creative Financing" including CD's and contracts, (which was awesome and well worth it, but then, I actually apply the information.

The answer was to lower expectations to reality or play 10 perfect hands in a row of blackjack or 10 perfect futures contracts in the market. 

It was always amazed at some agents that would spend $2,000 for a "jazzed Up" computer, but would not spend $500 to attend an out-of-town training session that could produce many thousands of dollars in return.  2.

Such as blackjack if you're counting cards.

i believe that most lenders won't count the rent as income if it is paid by immediate family (though it wouldn't qualify anyway unless its been on your tax returns for 2 years by most standards anyway). also, you are assuming incorrectly for probable vacancies. many states now require students to take atleast 1 summer session and many students will stay in the area regardless as they may have jobs or other obligations. when i lived in the dorms when i was in college, i used to hate it when the dorms would close for periods of time (ie between fall and spring term). such a hassle!

Blackjack may have a 99% payback.

As for what I have been doing towards the investment side, I signed up for guru trainings/seminars (nothing more than $100 per session), did direct mailings (postcards, hand written), made phone calls/text, bandit signs, drive for dollars, researched auctions. 

Wow, If anyone is doing a Flip Demo session in AZ I would definitely like to participate.