Concept in economics that relates to the sensitivity towards a change in price.


There are two extremes of elasticity: perfectly elastic and perfectly inelastic.

The demand curve for perfectly inelastic:

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                        Q
No matter what the price is, the quantity remains the same. An example of this is medical care. You go to the doctor for a checkup and he tells you that your veins are getting plugged up. You can go through the operation to get them cleaned, but it will be $12,000. You tell him "no thanks, I feel fine now and I see better uses for that money." A few weeks later you have a heart attack. When you're at the hospital, your doctor shows up and tells you that now you have to have that operation, but now it will cost $200,000. Since this is your life that's at stake, you'll pay that price - because the demand is perfectly elastic.

At the other extreme, the demand curve for perfectly elastic:

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                        Q
The price will stay the same no matter the quantity demanded. This typically occurs in a perfectly competitive market.

The way to determine elasticity is using the Elasticity Formula:

              percentage change in quantity demanded
     Ed =  --------------------------------------------
                    percentage change in price

If: 
    Ed > 1 , then elastic
    Ed < 1 , then inelastic
    Ed = 1 , then unitary
NOTE: Always put equation in absolute value (the reason is that price and quantity are inversely related).

There are also elements that help determine elasticity:

     1.  Number of Substitutes:
               few = inelastic
               many = elastic
     2.  Necessity vs. Luxury
               necessity = inelastic
               luxury = elastic
     3.  Portion of Income:
               large portion = elastic
               small portion = inelastic
     4.  Length of "Time" that the product has been profitable:
               short = inelastic
               long = elastic