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Archived updates for Wednesday, August 30, 2006

Empirical Evidence of Hindsight Bias

Thanks to Peter Zura's Two-Seventy-One Patent Blog for uncovering "Patently Non-Obvious: Empirical Demonstration that the Hindsight Bias Renders Patent Decisions Irrational," where Gregory N. Mandel discusses an experiment in which participant mock-jurors were given a hypothetical fact scenario concerning an invention. The scenarios were each based loosely on the facts of actual issued patents that were challenged on non-obvious validity grounds in litigation and were the subject of a reported decision.

Each participant received only a single scenario in one of three different conditions. The "foresight condition" (or control condition) included all of the lead-up information and ended with the scenario character trying to solve the identified problem. The "hindsight condition" was identical to the foresight condition except that it had one additional sentence at its end which stated that the character had come up with a solution, and stated what the solution was. The "debiasing condition" was identical to the hindsight condition, but the questions following the scenario included instructions based on Model Patent Jury Instructions that informed the participant of the hindsight problem, warned him or her about it, and advised him or her not to use hindsight in answering the questions.

According to Professor Mandel,

Because the only thing that varied between the foresight and hindsight
conditions was the presence of information concerning achievement of the
invention (i.e., because all other factors were controlled for), any differences
between the foresight and hindsight groups’ responses can be attributed to the
presence of this information. Similarly, because the only thing that varied
between the hindsight and debiasing conditions was the presence of the debiasing
jury instruction, any differences between the hindsight and debiasing groups’
responses can be attributed to the presence of this instruction.

. . . As expected, participants rated inventions non-obvious significantly more frequently in foresight than in hindsight in both the baseball scenario (chi-squared=25.203, Fisher’s p < .001) and the fishing lure scenario (chi-squared=10.623, Fisher’s p < .01). Descriptive statistics are presented in Table 1. For the baseball scenario 24% (10 out of 42) of participants in the foresight condition thought that a solution to the problem was obvious, while 71% (59 out of 83) of participants in the combined hindsight conditions thought that a solution was obvious (see Table 1). Results were similar for the fishing lure scenario: 23% (9 out of 40) of participants in the foresight condition thought that a solution to the problem was obvious, while 54% (44 out of 82) of those in the combined hindsight conditions thought that a solution was obvious (see Table 1).

. . . As expected, debiasing instructions had no significant effect on judgments of obviousness in both the baseball scenario (chi-sqauared = 1.079, Fisher’s p = ns) and the fishing lure scenario (chi-squared=.785, Fisher’s p = ns). Combining the hindsight and debiasing data across both scenarios similarly demonstrated no significant effect of debiasing instructions (?2 = 1.813, Fisher’s p = ns). Participants were no more likely to consider an invention non-obvious in the debiasing condition than they were in the hindsight condition.

Among Professor Mandel's extrapolations from this, and other, data:

  1. hindsight bias distorts patent decisions far more than anticipated, and to a greater extent than other legal judgments;
  2. neither the Federal Circuit’s suggestion test nor the Supreme Court’s Graham requirements solve the hindsight problem;
  3. the admission of secondary consideration evidence does not cure the hindsight bias;
  4. jury instructions that explicitly identify and warn against the hindsight bias do not ameliorate its impact; and,
  5. the hindsight problem pervades patent law to an extent not previously recognized—it biases decisions under the doctrine of equivalents, claim construction, the on-sale bar, and enablement.
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3 Comments:

Anonymous Anonymous said...

Comment from Europe: Nice report of a piece of research that uses scientific method to confirm what was always "obvious" to everybody skilled in the "art" of patent infringement and validity. The EPO "Problem and Solution Approach" has always taken a lot of ignorant and unfair academic criticism. Maybe that will abate just a little, when people find out that P&S eats hindsight for breakfast.

August 26, 2006 3:26 AM  
Anonymous Anonymous said...

Those who have experienced the problem-solution approach applied during opposition by the EPO know that it does not avoid hindsight. The reason: the so-called "problem" is written subjectively in hindsight to make the claim inventive or not (depends on how the examiners feel that day). Thus, the report confirms what is in fact applied in the EPO, also.

August 30, 2006 7:04 PM  
Anonymous Anonymous said...

Dear Respondent, you make my point. P&S eats Hindsight for Breakfast by dealing with it up front, and disposing of it as an issue, before one gets to the heart of the matter,namely, whether the state of the art at the date of the claim renders anything within the scope of the claim uninventive. At that stage of the EPO analysis, hindsight is strictly excluded. At the breakfast stage, hindsight knowledge of the invention is relied upon, but only to the extent of discovering from the patent what the inventor says about the technical field he is in, and what problem he was addressing. It is mindless, to ask "Is it obvious" until you know the objective "problem" (just as it is mindless to ask "Is this Trademark descriptive" till you know what are the goods).

The proof of the pudding is in the eating. If P&S is flawed because it invokes hindsight, why is it so universally accepted, by those who use it, day in day out, one day as patent owner, the next as Opponent? Ask the pharma boys.

But you are right that the outcome depends on how the Examiners are feeling that day. That's the civil law world for you. Common law would decide the issue on the evidence. Much fairer, but much more expensive. Civil law relies instead on the second instance, the appeal, to get it right, at a second bite at the cherry.

August 31, 2006 3:26 PM  

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