Decision Anchoring
A nice summary of how results can be anchored just appeared on the web. This human behavior has great implications in business and technical decisions.
Anchoring sets a biased context for estimation. It is a cognitive limitation that affects the quality of our decisions. Anchoring occurs, for example, when a manager asks for an estimate with something like: "I don’t see how we could commit more than $10,000 to this." $10,000 now becomes the anchor point. This stated amount biases all the following estimates that are generated.
Anchoring can happen in subtle ways. Let’s say you are bidding on a project and you have been led to believe that the customer has a ceiling of, say, $10,000. You are now anchored to this value and will make decisions to try to force your project to fit it. This only seems logical, but it has interesting effects. First, the amount of work you propose will be descoped to fit the budget. But people always are optimistic, so, if you get the job, you will still have more work than money. Then begins the dance of working more for less money (overtime), further descoping or asking for more money. This dance is further discussed on pages 82-85 in Making Robust Decisions.
To demonstrate anchoring, I gave a group of people a simple estimation problem - asking them how long it would take them to wash a list of dishes. I described the dishes in detail, how dirty they were, and what "wash" meant. The mean estimate was 32 min with a standard deviation of 10 min. I then asked another group of subjects to estimate how long it would take to clean the dishes exactly as before, but this time I added "Your partner has told you that the kitchen needs to be clean in 15 minutes." This anchoring resulted in a new distribution with a mean of 18 minutes and a standard deviation of 6 min.
Think of the implications on decision making. All decisions are based on best estimates of past performance, assessments of the current situation, and visions of the future. Every one of these can be clouded by anchoring. You cant totally avoid it. However, you can be aware of how you word your need for information and consciously try not to anchor estimates on which decisions will be based.
Anchoring sets a biased context for estimation. It is a cognitive limitation that affects the quality of our decisions. Anchoring occurs, for example, when a manager asks for an estimate with something like: "I don’t see how we could commit more than $10,000 to this." $10,000 now becomes the anchor point. This stated amount biases all the following estimates that are generated.
Anchoring can happen in subtle ways. Let’s say you are bidding on a project and you have been led to believe that the customer has a ceiling of, say, $10,000. You are now anchored to this value and will make decisions to try to force your project to fit it. This only seems logical, but it has interesting effects. First, the amount of work you propose will be descoped to fit the budget. But people always are optimistic, so, if you get the job, you will still have more work than money. Then begins the dance of working more for less money (overtime), further descoping or asking for more money. This dance is further discussed on pages 82-85 in Making Robust Decisions.
To demonstrate anchoring, I gave a group of people a simple estimation problem - asking them how long it would take them to wash a list of dishes. I described the dishes in detail, how dirty they were, and what "wash" meant. The mean estimate was 32 min with a standard deviation of 10 min. I then asked another group of subjects to estimate how long it would take to clean the dishes exactly as before, but this time I added "Your partner has told you that the kitchen needs to be clean in 15 minutes." This anchoring resulted in a new distribution with a mean of 18 minutes and a standard deviation of 6 min.
Think of the implications on decision making. All decisions are based on best estimates of past performance, assessments of the current situation, and visions of the future. Every one of these can be clouded by anchoring. You cant totally avoid it. However, you can be aware of how you word your need for information and consciously try not to anchor estimates on which decisions will be based.
Labels: anchoring, cognitive limitations in decision making, decision making, estimates
Posted by David G. Ullman at 6:28 AM
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