There are stistical measures for the valuation of a lease, you'll need extensive research as to the market and you can ask a good MAI appraiser may do that in your area.I would probably discount future rents at 18% until lease up and 12% over the remaining term as a simplistic approach.Your discount has much to do with the potential of landing a strong tenant, I'd guess you're looking at decent tenants for that amount of space, taking it all, but you may need to break it down to smaller spaces, higher rents but also small tenants are usually not as strong, so it's at a higher risk too.

Here is the link and below is a screen shot.Watch the getting started video for details but simplistically enter the estimated rent and some other known factors and click Estimate.

I know this question is probably very simplistic to most people.

If you look at everything that @Joe Villeneuve said, I hope you now realize that there is MUCH more information required to analyze possible deals than any simplistic 2% "Rule of thumb".

Just thinking this through, and though I would put this out there and get BPers thoughts.Overly simplistic example:You purchase a 100 unit class C multi family in a class B area.

The reason I liked the guide was due to the simplistic approach it took about the basics of financing, identifying prospective property, and budgeting - I agree some of it is not best practice. 

Reason's I've retained:Minimize your own cash in a deal.Use someone else's cash to buy a property (the bank) and another person's to pay off the loan (the renter).Buy more properties (simplistic example: buy one 100k property cash, or finance four 100k properties). 

I also would have never noticed these deficiencies in  REIFAX if it wasn't for me being trained on using Matrix and seeing firsthand how detailed the searches on the MLS can be.I know what I have just said is extremely simplistic and basic to the more experienced investors on this site.

That is how all new things should be treated until some proof is in.I have seen those machine appraisals and they were simplistic at best.

At a minimum, your best bet would be to use your time to figure out how to answer all such questions before getting your hands dirty.Not only is this a very simplistic example, but even considering that there are a number of other questions that could arise, especially as you add the complexity of legality in real estate.