Coefficient Of Dispersion

Definition of "Coefficient of Dispersion"

The coefficient of dispersion is how municipalities can determine differences between the assessed values of properties in an area or neighborhood. It gives a broader look at the state of the market, and a way to evaluate how consistent the appraisal of the properties is. The definition of the coefficient of dispersion that is used exclusively in dealing with market values and properties is a measure of how much values of a particular variable vary around the mean or median. The end value is represented in percentage from the median.

 

The Coefficient of Dispersion’s formula:

coefficient of dispersion formula 1

 

COD = coefficient of dispersion

N = number of properties in the sample

EPi = appraised value of ith property 

SPi = sale value of ith property

∑ = summation of all the values in the group

 

How to Calculate the Coefficient of Dispersion?

After that insane formula, we understand if homeowners want to stay clear of it, but there are reasons why any homeowner would want to use it. If, for example, you’re house was appraised at a value that is higher than you expect, and the same happened to other neighbors, you can figure out if this is a trend in the area to increase taxes or just the increase of the market value in the area.

Example:

John investigated and managed to find the appraised value of 7 properties around him as well as the actual price for those properties. 

 

Appraised Value

Sales Price

359,000

370,000

362,000

373,000

347,000

358,000

329,000

340,000

384,000

396,000

372,000

386,000

395,000

396,000

 

Now, John finds out the median appraised value by adding all the appraised values, then dividing it by seven properties ($362,000) and does the same to the median sale price ($373,000). With these values, he can start using the formula.

 

coefficient of dispersion formula 2

 

The median appraised value divided by the median sale value is 0.9729.

John returns to his table to discover the EPi/SPi for each property because the ∑ requires him to discover that value independently for each before he subtracts 0.9729 (the median EPi/SPi) from each:

 

Appraised Value

Sales Price

EPi/SPi

359,000

370,000

0.9702

362,000

373,000

0.9705

347,000

358,000

0.9692

329,000

340,000

0.9676

384,000

396,000

0.9696

372,000

386,000

0.9637

395,000

396,000

0.9974

 

With that out of the way, John needs to subtract 0.9729  from each value. Here he considered negative values positive:

 

Appraised Value

Sales Price

EPi/SPi

EPi/SPi-0.9729

359,000

370,000

0.9702

0.0027

362,000

373,000

0.9705

0.0024

347,000

358,000

0.9692

0.0037

329,000

340,000

0.9676

0.0053

384,000

396,000

0.9696

0.0033

372,000

386,000

0.9637

0.0092

395,000

396,000

0.9974

0.0245

 

Now that he has all the data necessary, John can work the formula:

 

coefficient of dispersion formula 3

 

The coefficient of dispersion is a complex formula but the example above tells us that the average difference the houses have from the median of the assessed sales ratio is 0.75%.

 

 

Comments for Coefficient Of Dispersion

Kc Minck Kc Minck said:

COD example unclear

Jan 15, 2023  09:18:18

 
Real Estate Agent

Hello. Let us shed some light on this. 

Someone wants to find out the appraised value of several properties around them. and the sale price is higher. Then they discover the median appraised value ($362,000). They add all the appraised values of all the properties and divide them by the number of properties. And later does the same with the median sale price ($373,000) The median appraised value divided by the median sale value is around 0.9. Then, they calculate that the average difference between houses and the median is 0.75.

Jan 20, 2023  09:22:24
 
 
image of a real estate dictionary page

Have a question or comment?

We're here to help.

*** Your email address will remain confidential.
 

 

Popular Real Estate Terms

An anticipatory breach of contract is the action that occurs when one party in the contract shows their intention to not fulfill their contractual obligations to the other party. The ...

Civil rights acts passed by the U.S. Congress includes those of 1866, 1870, 1871, 1875, 1964, and 1968. The first two acts gave blacks the rights to be treated as citizens in legal actions, ...

The right of a landowner to have lateral land support from adjacent properties. The right of lateral and subjacent support means that an adjacent land owner may not, for example, lower or ...

The return by owners of a property investment usually through a depreciation allowance. a clause in a contract permitting the prior owner of real estate to recover under certain ...

If you are involved with real estate, chances are you've come across the term "convey" or conveyance. But what does convey mean in real estate? This term is crucial whether you're buying, ...

The right to recover property taken away by foreclosure by paying the lender the total amount owed plus foreclosure costs. The right of a debtor in bankruptcy to recover personal ...

(1) Individual or business that is engaged to do some sort of construction work for another for a fee. There are basically three types of contracting: A general contractor enters into a ...

Divider made of plasterboard or plaster used to partition rooms. A room is created by the walls surrounding it. ...

The definition of a service fee or brokers fee in real estate is a flat fee paid to a real estate agent or broker in addition to the commission for the sale or purchase. This is to cover ...

Popular Real Estate Questions