- Find a statistic, _any_ statistic, that goes up this month,
- Publish that statistic in as positive a light as possible. Ignore other statistics, even the one you used last month.
Under no circumstance will they publish pessimistic statistics. Just something peculiar about the field. Try talking to a realtor: the deal they are presenting you is always a great one, one that you should take _now_.
My uncle's real estate page for Wake County in North Carolina shows similar figures: http://kengramley.com/city.php
That's calculated directly from the county's tax data. It's a bit out of date; from February, I think. I'll see if I can get some new data up soon.
Some people are actually interested in telling the truth, not misleading you. It's rare though, I'll grant you that.
Btw, he was an engineer before he became a realtor, and if you must know I am the "webmaster". Yes, it could be construed as shameless promotion, but it is relevant.
Edit: I don't know if it's clear enough - the data is year over year.
The reason the year over year numbers are more useful is because they give us a "statistically meaningful" result. Because the year over year confidence interval is -49% to -33.2%, we can very confidently say the numbers are significantly lower this year than they were last year. Again, that's not because it's a year over year number, but because the confidence interval is no where near zero. 90 out of 100 times we would expect the data to be between -49% and -33.2%. In fact we can go even further. If this is a true 90% interval, we can calculate that 1 standard deviation is 4.79% and a 3 standard deviation range would be (-55.46%, -26.74%) this means that we would expect our observation to fall within this confidence interval 99.7% of the time. Notice that we can with a high degree of confidence state that that year over year numbers experienced a significant drop. For kicks and giggles let's look at the month over month number. 1 standard deviation is 11.09% and 3 standard deviations is plus or minus 33.27%. Meaning that our 99.7% confidence interval is -28.57% to 37.97% So our true value lies somewhere from housing shrinking from 28.57% to growing 37.97%! So we can't say with any statistical certainty that housing numbers decreased by 1/4th or increased by 1/3rd! That standard deviation is absolutely monstrous. So the problem isn't that month over month is unimportant and year over year is more important. It's that based on the numbers we just don't know what the actual month over month number is - we don't with any measure of statistical certainty know if it's actually up or down. Whereas with the year over year number we know with virtual statistical certainty that it is substantially down.
* one quick note - typically 95% confidence intervals are used because they reduce certain types of errors in your conclusions. I expanded the range to a 3 standard deviation range primarily for illustration purposes. I hope it helped rather than confused. Statistics is packed full of jargon and technicalities, and it's easy to project incorrect conclusions if you aren't very precise with your language.
edit, I just noticed it's a 90% confidence interval and not a 95% confidence interval. My original numbers above were based on a more typical 95% confidence interval which would represent 2 standard deviations. 90% Confidence intervals are 1.65 standard deviations from the mean. I've adjusted my 3 standard deviation ranges accordingly.
Then it is noise and irrelevant.
And any other year of this past century, year over year numbers would mean something, however this is the one exception.
Month on month tells us nothing (in this extreme example). Year-on-year (ie, Oct 09 v Oct 08) give us an indication of strength or otherwise in a market, without seasonable variations.
Having worked with 120+ Real estate agencies (in Australia - US cycle will differ) I can tell you that every year Jan will be 'down' from Dec, Feb will be up, September will always show an increase over August, and Dec will usually be bigger than Nov.
Reporting just those figures would look like the 'housing market' was an unpredictable roller coaster - up one month, down the next, when will it end, think of the children!?
Sure, in many instances (your business cashflow, for instance) both data points are useful. But year-on-year removes more variables and is therefore more important.
To reiterate (and not to clarify, because my original comment is clear): When the press reports rises and declines, if they do not explicitly say year over year, they are talking month over month. Indeed, this VERY article contains an example of it, with the press reporting that home sales were up 4.7%. The original title of this submission, before it was edited to include "year over year", specifically played upon this implied and incorrect comparison to provoke a response.
Indeed, I'm not the only one who found the headline misleading; my comment had been voted up to at least 5 shortly after I posted, and before the headline was altered and your tangential comment sent people on a wild goose chase.
As JacobAldridge points out, it is used to account for seasonal variation; an article that looks to month over month figures would seem anomalous for this same reason. But it takes knowing some of the nuance of the industry and how it is reported to understand the what and why of the convention. I'm not a realtor, nor do I work with realtors; I just find that sector interesting to read about, enough so that some of the nuance rubs off. :-)
I actually can't think of any sales figures that are relevant month to month.
Basically any way you slice it you can argue the other person is full of shit. That doesn't mean anyone actually is.
Ellyagg also said "This post's headline is needlessly provocative and misleading." , which prompted me to respond.