A General Theory of Physician Prescribing Behavior

S. Kent Stephan
PRINCETON BRAND ECONOMETRICS

A doctor’s first detail on a new brand is usually decisive. Brand perceptions created in those few minutes will very likely govern the doctor’s prescribing far into the future. In most cases, a doctor’s perceptions of a brand will remain virtually fixed until the next important new brand enters the category.

Brand perceptions formed before the first script is even written are very unlikely to be changed later on by either the doctor’s clinical experiences with the drug or ongoing promotion. In fact, an average doctor’s initial perceptions will actually be reinforced by his clinical experiences, rather than changed. Ongoing promotion (details and journal ads communicating current claims) may make the brand more prominent in the doctor’s mind, but will not make him perceive it any differently.

Conventional wisdom paints a very different picture. It is based on the long-standing assumption that a doctor’s brand perceptions are shaped to a large degree by his prescribing experiences. Consequently, the first detail is thought to serve the primary purpose of simply getting the ball rolling by showing the doctor that the brand is worth a try. Later, clinical observations and possibly ongoing promotion are expected to then take over to determine where the brand ends up in his mind.

One consequence is that conventional wisdom seems to have caused pharmaceutical marketers to view the role of marketing communications differently from package goods marketers. Package goods marketers use advertising to make their brands desirable. With them the main emphasis is on the message.

Pharmaceutical marketers, on the other hand, often use marketing communications at launch to present relevant facts and create brand awareness. The quality of trial, i.e., why the doctor writes the first script, is rarely an issue. It is often incorrectly assumed that a doctor’s initial perceptions will have little bearing on how he evaluates a brand’s performance after he has prescribed it.

Later, after an Rx brand has become established, promotion is used to sustain brand awareness. There is often a concern that doctors may forget about a brand and, as a result, stop writing it. This concern confuses causes and effect. Prescribing itself sustains brand awareness. Doctors forget about brands after they have stopped using them.

The conventional wisdom that clinical observations determine brand perceptions underlies most major decisions for promoted brands. It underlies how promotional resources are budgeted and deployed. It underlies how new product planners focus their efforts. It underlies message strategies. It underlies the decisions sales representatives make every day.

Unfortunately, conventional wisdom conflicts with the actual evidence, misrepresents the real world and leads to wasteful decisions. Over a typical brand’s lifetime, conventional wisdom will easily cost it $100 million or more – often much more – in achievable profits.

Here is the evidence that refutes conventional wisdom. It establishes that perceptions are fixed early on and rarely evolve over time in response to clinical observations or ongoing promotion.

1. Tracking studies for a variety of aggressively launched brands show that doctors’ perceptions a year after launch were statistically the same as they were only a month after launch.

The first year is tumultuous for a new brand. This is when most prescribers write their first script. It is when detailing and journal advertising are at their heaviest. Yet, even in large, highly competitive categories, perceptions at the end of 30 days have without exception been statistically indistinguishable from those measured at the end of the first year.

2. If doctors actually tried new brands on a few patients and observed the results, as most marketers believe they do, one would surely see a gap in their prescribing while the observation period was going on. Careful analysis of doctor level prescribing data for a variety of new brands has failed to uncover such a gap ever.

3. Analysis reveals that, all else being equal, the more details it takes to generate the first script from a doctor, the less the doctor will prescribe the brand long term. If doctor’s perceptions were shaped by their clinical observations, it would not matter over the long run how much effort it took to generate the first prescription. The average doctor, who prescribed the brand in response to only one detail, would eventually end up at about the same place as other doctors who needed more details to see the brand as an acceptable choice for at least one patient. This is not what the data show, however.

It is because brand perceptions remain stable following the first detail that Princeton Brand Econometrics is able to accurately simulate the adoption of new prescription brands and forecast Rx’s with single digit accuracy. This is accomplished by measuring doctors’ responses to the message before the product is even launched, translating these responses into real world behavior and then applying models that account for the marketing mix. This forecasting success also flies in the fact of conventional wisdom.

We submit this General Theory of Physician Prescribing Behavior. This Theory fits the data and, more importantly, accurately predicts outcomes. The Theory, in effect, makes the case that prescribing behavior is governed by rules that apply across categories. In the right hands, these rules can be used to make doctors’ prescribing behavior extremely predictable, under any given scenario.

I. The first detail creates brand perceptions that persist long term, particularly if the doctor later prescribes the brand. If he does not prescribe the brand, his perceptions will remain somewhat malleable to promotion up until he does.

However, with each successive unproductive detail, the odds that the doctor will even write the brand drop dramatically and predictably. Even if the doctor eventually begins to prescribe it, he will give the brand a far smaller share of his category Rx’s than will comparable doctors who responded to fewer details. When a doctor fails to prescribe a new brand in response to a detail, it is because he still does not see how it represents an acceptable choice for even one of his patients!

Sales representatives regularly squander valuable time on heavy category prescribers whose unresponsiveness to detailing has, unbeknown to the representatives, established the doctors’ low potential for prescribing the brand. Representatives plow ahead convinced that if such a doctor were to just write a few scripts, he would end up prescribing it with the same frequency as comparable doctors who were earlier adopters.

Unfortunately, high category prescribers who are late adopters will be much less important to a brand than certain earlier adopters who write the category far less. (Pre-launch modeling and post-launch adjustments that account for doctors’ responsiveness to detailing at each step along the way will increase the productivity of one’s detailing dramatically.)

II. If a doctor begins to prescribe the new brand, his "clinical observations" will reinforce his perceptions rather than change them. This conclusion is not only consistent with tracking studies, it also is consistent with the finding in unblinded clinical trials that doctors tend to see what they expect to see. Having one’s expectations met is reinforcing.

If the doctor initially perceives some advantage to the brand, his clinical observations will reinforce this perception. If, on the other hand, he has been cajoled into trying a brand that looks to him like a me-too, his clinical observations will reinforce this perception.

In both cases, the doctor’s long term level of prescribing and responsiveness to promotion will reflect his perceptions. A brand that is perceived to be a me-too will require heavier promotion to sustain fewer Rx’s in the same competitive environment than if it were perceived to be superior in some meaningful way.

III. Ongoing promotion alone can rarely improve a doctor’s perception of a brand he has been prescribing. On the other hand, it can and often does generate incremental Rx’s by making the brand more top-of-mind. However, this is an expensive way to use promotion to grow a brand.

Ongoing promotion should be used to make an attribute, on which the brand is perceived to be a winner, carry more weight in the doctor’s decision process. The object is to influence how the doctor trades off the perceived benefits of a competitor for the perceived benefits of one’s own brand.

For example, he might perceive that one’s brand, Brand A, works faster than Brand B, but that this advantage is negated because he also perceives that Brand B relieves certain symptoms better. In this example, Brand A’s message should focus on showing the doctor why speed of relief is so important.

Exploiting winning perceptions of a brand represents a much more financially rewarding use of promotion resources than simply hammering away to make the brand more top-of-mind. Unfortunately, hammering away seems to be the prevalent approach.

IV. There are three identifiable patient groups that have tactical significance for any brand that has made it into a doctor’s armamentarium. These groups result when a doctor: (a) perceives important differences among the brands he uses and (b) perceives that his patients have different needs.

A significant amount of brand switching results simply because patients with different needs will show up in a doctor’s office from one time to the next. This brand switching occurs in the absence of competitive promotion, but is often incorrectly assumed to result from competitive promotion.

Some patients are out-of-bounds to the brand because the doctor clearly perceives a competitor to be the best choice. The brand in questions is not even considered when one of these patients shows up in the doctor’s office.

Frequently, representatives target high prescribers who give their brand low shares. The assumption is that the remaining business represents upside potential. In fact, the real upside will be small if many of these category scripts are going to patients who are out-of-bounds.

(Note: Incentive plans for field representatives frequently assume that it is possible to get a 100 percent share of category Rx’s through diligence and hard work. This assumption is normally so far from reality that the true differences between high and low performers are obscured.)

The second group is patients who are in-the-bag because the brand in questions is clearly perceived to be the best choice. This business is nearly impervious to current competitors and requires little promotion to sustain. The more in-the-bag patients there are, the more profitable the brand should be because these scripts are inexpensive to gain and sustain.

Just as brand cannot compete for patients who are out-of-bounds, patients who are in-the-bag are its rock-bottom baseline. These Rx’s will remain even after all promotion has been withdrawn.

(Note: As a rule, the larger a brand’s share, the larger will be the portion of its scripts that are going to patients who are in-the-bag. This relationship, and not the share per se, is why leading brands have been found to be more profitable than their smaller, non-niche competitors.)

Financially successful marketing starts with positioning the brand in doctors’ minds in a way that will create as many in-the-bag patients as possible. This must be accomplished with the first detail. Using the first detail just to show that the brand is worth a try wastes this one-time opportunity.

The third group is patients who are up-for-grabs because the brand in question and at least one other are perceived to be equally acceptable choices. This does not mean, however, that the brands are necessarily perceived to be equivalent. They may simply offer different benefits that offset one another. A doctor’s prescribing to up-for-grabs patients will respond most to ongoing promotion.

Once a brand has become established, this up-for-grabs group should be the focus of one’s marketing and sales efforts. It is possible to identify and quantity these marketing opportunities at the doctor level with precision.

V. The most common reasons for a doctor’s perceptions to change, after he has had used a brand, are: (1) an improvement in the product itself, such as a long acting form, a new delivery system, or a new dose; (2) new clinical trials results; (3) new claims; or (4) entry of a new competitor. In the last case, perceptions will usually be degraded. Successful new competitors usually diminish perceptions of existing brands on one or more critical attributes.

There are very significant message development, resource allocation and portfolio management implications to the Theory that merit discussion at a later date. There is one salient point that bears brief mention here, however.

Packaged goods marketers take brand positioning very seriously. They begin the process early on, and involve their ad agencies. In fact, agencies that cannot contribute in a major way strategically are not given new product assignments.

Package goods marketers work to develop a large number of different ways of looking at the brand, consistent with expected labeling. They undertake simulations, using well-validated models, to determine how large a business each of several different positionings would pull in, before deciding which way to go. They know that the basis of good decision-making is to reduce the amount of guessing that takes place.

Package goods marketers know that one feasible positioning could very easily result in a much larger business than another for the same financial investment. This is just as true for pharmaceutical brands, but many pharmaceutical marketers must change their ways to take advantage.

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