Numbers rarely lie but the interpretation of them is sometimes rather suspect.  

they have to lag behind to a certain extent. The MLS would be the most current at all times but the media doesn't really have direct contact with that info. Even NAR is a month behind.

Reported numbers are (presumably) facts.

Forecasts are conjecture, hypothesis, or speculation.

Lag time?  A few days, perhaps a week.

I am not sure I understand the question or more specifically what real estate numbers you are referring to .... and reported by whom. 

I'd like to believe my MLS is relatively current and accurate.  

It all depends on which numbers, the source of the numbers, the organization reporting on the numbers...  I do my market reports 5 or 6 days after the end of the month. So my numbers lag by 5 or 6 days. I suspect many of the national reporting machines are probably a few weeks delayed.

Usually lagging numbers.  Just read a report about March 2021's numbers compared to March 2020 (my area is up 12% in median price and 25% in sales volume).  Any type of reporting is always going to lag behind.  Forecasting the market is less accurate than forecasting the weather.

When you mention "numbers being reported at all levels" you are casting a very wide net, Peter. Yes...some numbers are lagging numbers. Yes...some numbers are a forecast.

Peter,

I am in the same camp as Michael Jacobs when it comes to numbers.  A

It is in how the user wants to be portrayed most times!

It depends on the report. The MLS would seem to be the most up to date and most accurate...so we are in a position to be the most accurate and up to date as opposed to the media and others.

Data is always vulnerable to human error but remains a good rule of thumb

The MLS numbers in our market are good indicators.

Michael Jacobs sums it up well.

It is the nature of things being reported, I suspect that electronic reporting has reduced this lag significantly over the past few decades.

The news accounts are always lagging, but I do a daily tally of the new listings and total listings plus pending/closed.

Yes, those are stats that are reported after the fact. Forecasts are just educated guesses.