Most Multiple Listing Services offer Activity Reports of some kind that break down data on a month by month basis, from year to year. I have found that closing my listing presentations with this information helps to give a potential selling client the "big picture".
As an example, in my last 6 listing appointments, I have added Activity Report comparisons with the most recent month in 2008 vs. the same month in the previous year (2007). In every one of these appointments, I "got the listing".
Note: For me on Long Island, that's a total of $2,560,000 (approximate) in inventory, which translates to more buyer traffic, increased agent networking (as they call to show my inventory) and approximately $60,000 (minimum) in revenue. That $60,000 does not include all the possible buyer leads I accumulate, plus the additional listings I will obtain in the area via sign calls.
Back to the Activity Reports and their effectiveness during the listing presentation. As a whole, I feel if I focus too much on the specifics of the area, the homeowner gets lost or worse, caught up in how their neighbor is priced. I want to avoid this because if their neighbor is priced too high, then this puts me in the defensive position of trying to explain why I must price the home lower than their neighbor.
I end my listing presentations with strong data in the Activity Reports. In my local market, comparing July, 2007 Total Closing Gross Volume To Date (January to July, 2007 = $2,487,794,200) vs. July, 2008 (January to July, 2008 = $1,753,808,300), I point out to my homeowner a decline of total gross volume in sales over $730,000,000. That's a "big picture item" that let's them know, without a doubt, the market has slowed. Additionally, I compare the declines in listing prices, contract prices and closed sales in the respective months.
Another item I focus on is total inventory. One thing I've noticed is people confuse a what they hear on television. They will hear something like, "...increase in sales..." and interpret that as "...increase in sales prices...". What information they may be hearing is based on sales vs. inventory. Say that in July 07 there were 3,415 total active listings with 168 closings in a given zone or area of the state and in July 08, there were 3,151 total active listings with 156 closings in the same zone, etc.
Taking that at a national level (or local), one could interpret that as higher sales volume - aka "increase in sales..." When really, the good thing to point out is that the market is taking on less listings (which is good for sellers) and that sales ratios are increasing (and I'm one of the agents involved in making that happen!). However, both of these positive indicators are severely lagging behind the negative data. I use the decline in sales price data from each respective month to prove this point - prices must come down in order to move the inventory.
The Activity Report, shows my homeowners, that I am in total command of the information as a whole, not just in their local little neighborhood. I can also use this data to deflect away from squabbling about a neighbors house. The market is much larger than the neighbors house, but I don't have to convince them of that. I simply introduce this overall "big picture" and they forget about the neighbor.
Most importantly, as I hit a few highlighted items (yes I use a highlighter to point out items of interest), I find that my listings are priced good, which means, they get showings and when I show it, I generally convert buyer loyalty at a higher frequency because they see me as someone who knows real estate (which I do).
So, if your local MLS has an Activity Report, then you should definitely take advantage of it in your presentations. If they do not have one, then you would be wise to write the local board, talk to your broker and get the word out. You pay membership fees for a reason.
The Activity Reports on my local MLS helps me to focus homeowners on big picture items and it really does help me know the market place that much better.
Good luck!