Joe's answer is the most accurate.

Another one I think is huge is the lack of accurate information.

You need a complete and accurate income statement (profit & loss). 

I noticed the CMHA fair market rent is showing $2,300 for a 3 bedroom in the 44122 zipcode. https://www.cmha.net/housing/landlords/rent.php Anyone know how accurate are these rental rates on their website and what one can expect to collect?

PadSplit / co-living are just now becoming popular around this area but the problem is determining the rents so I can perform my underwriting accurately.

For example, if a client gives me the income and expenses on the rentals and it does not include mortgage interest, taxes, insurance or repairs, I have a follow-up question just to confirm that information is accurate.

Airdna has been fairly accurate for our other STR which is averaging close to 3k/month this year with the peak STR season being fall as we're located near two universities (football season).

Man, if everyone did their research more about Dave Ramsey before posting on here instead of just saying “well I heard” then we would have a lot more accurate information in this thread. 

I see that HUD has historical data per zip code here (40th percentile of the rent prices in the area used for section 8):https://www.huduser.gov/portal/datasets/fmr/smallarea/index....I'm not sure how accurate is their data in some of the zip codes.Here data data is broken down by bedroom count so you can get and idea if it's a house or an apartment depending on the area and room count.Zillow data is limited depending on the zip code.

@Yvonne Wang Use this website to cross check for zoning and whether the permitting is in place. http://atlas.phila.gov   It's a good website with accurate reporting.