I don't think of this in terms of "causes of homelessness". These are different categories.
The "visible" homeless, ironically, are extremely difficult to measure. They often don't carry or won't present identification, they often have no family or support structure, they often make little to no attempt to use services.
The "invisible" homeless are the opposite, and can be easily measured, because they have all of those things.
When you see numbers trying to measure homeless people, it will almost always be the "invisible" homeless. Sending people out with clickers to count the homeless people on the street is nearly impossible, so the best we can do is various sampling approaches with huge margins of error.
The "visible" homeless, ironically, are extremely difficult to measure. They often don't carry or won't present identification, they often have no family or support structure, they often make little to no attempt to use services.
The "invisible" homeless are the opposite, and can be easily measured, because they have all of those things.
When you see numbers trying to measure homeless people, it will almost always be the "invisible" homeless. Sending people out with clickers to count the homeless people on the street is nearly impossible, so the best we can do is various sampling approaches with huge margins of error.