I attribute this to patience in the leasing process and care in screening tenants.

However, if you have ever bought a house at auction (@Hal Thompson has so I'm sure he'll concur), or seen the inside of a just foreclosed house before the bank has had it cleaned out - well, there are lots of owner occupants (not just renters) living in conditions that are similar, and attributing the situation to substance abuse is just stereotyping and might not be quite true.

And how do you know whether to attribute performance  to 1) the property/condition , 2) the tenant being rough on the property 3) cost of doing business, normal occuranceoff the top of my head I'm thinking:Days to close out an issueTimeliness in responding to issuesAnnual/quarterly repair expenses# of repair request per yearOr even how do you know whether or not your getting better at landlording /property management over time?

You have to use the whole population not a subset in your calculations.China population 1,396,164,036 Covid 19 cases 80,754 = .00578% deaths in China attributed to Covid 19 cases 3,136 = .00022%https://www.livepopulation.com...I'd be a lot more worried about a 'quake in SeattleWashington’s 30-year earthquake drill for the ‘Big One’: Order studies.

At least in my area and after doing some research with the city; appears that if any house is currently being used as a Multifamily (3+ units)....or can have documented use (such as a utility bill) of being used as a multifamily in the last 2 years, then it  can continue to be used as a multifamily.However, without these attributes, then the town ordinance does not allow for multifamily and everything in town is zoned as single family (SFR).  

I attribute those to tenants being stuck at home. 

Since the property seems to have had deferred maintenance what can I attribute to that?  

I attributed it to the heaven rain fall we were getting at the time.

I need specifics - specific attributes, methods and ways of obtaining data to quantify. 

This growth can be attributed to the cities' strong job markets and low cost of living, making them desirable locations for people to live and work.