Outwitting Zipff’s Law!

In our marketing excellence themed month, Chris Rose discusses how to change the rules by which we launch new pharmaceutical products and outwit Zipff’s Law.

I am sure that somewhere the debate rages on as to the validity of Zipff’s law! Before “marketing led” became the vogue Zipff’s law reigned supreme; share of voice and level of differentiation could balance out a late market entry and often did in the days of “mega field forces” to launch the latest “me-too mega brand”.

However, as we in pharma marketing build our understanding of effective positioning we can start to outwit Zipff’s Law or at least start to change the rules by which we launch new products.

“…Share of voice no longer mattered if the payor did not put your product on the formulary”


Zipff’s Law can be illustrated by going on a journey; the goal is to get as far possible down the road! This can be achieved by:

1. Starting the journey before the other team arrives i.e. Being first to market, a good head start is usually difficult to beat!

2. Street fighting! i.e. increasing your share of voice, the more support you have the easier it is to push the competitors back!

3. Having the best road racers i.e. differentiating from the competition, if you are the fastest then the chances are the competitors won’t be able to catch you!!

If you all stick to the same road then using the principles of Zipff’s law will enable you to become the game wining (market leading) team!

Or you could!!

As our customers became more knowledgable and began to employ a new group of experts to make purchasing decisions it became more and more difficult to play to Zipff’s rules! Share of voice no longer mattered if the payor did not put your product on the formulary! Level of differentiation was irrelevant if patients no longer adhered to treatment.


“Level of differentiation was irrelevant if patients no longer adhered to treatment.”


Luckily some in the industry realised that physicians were reacting negatively to the “push, push” of messages by multiple field forces and some switched-on leaders started to look for different ways to compete.

So what can be done to outwit the heavy hitting, high spending market leaders of old?

Well the first option is change the game or you can move the customer base!

Changing the game!

In pharma the tradition has been to beat a competitor in the area which is believed to drive physician choice, usually efficacy. Throughout the 20th century (and into the 21st!) the traditional sales aid will have a histogram with an efficacy chart showing that your product is better than the other products, usually accompanied by a picture of a smiling patient! (marketing was unbelievable easy in those days! Simply find the one efficacy parameter in which your product excelled and push it as hard as possible to the prescribers of the competitors, with a pen and pad to remind them!).

Changing the game is all about continuing to work with the current customers but finding out what really drives the choice and developing those elements of your proposition which will meet the true needs of the customer, understanding how choices are made at different levels of consciousness and based on different levels of needs is essential. Strategically this could be a “by-pass strategy”.

“…what can be done to outwit the heavy hitting, high spending market leaders of old?”


Let me illustrate this with an example. I once launched a product where the 1st to market had focused on efficacy, owned that position (and incidentally had much better efficacy data than we did!) We had to “by-pass” them. We achieved this by making efficacy a class effect and moving the game on to focus on usability of the product and the emotional “win” of the prescribers.

Imagine the competitor was going up the road on an efficacy ticket, we came along and said yes efficacy is important but it is no use if the patient does not take the drug. We will help to ensure the patient takes the drug with increased patient services, patient-friendly delivery of the product and, most importantly to the prescriber, ensure the patients were happy with their choice of therapy! We took the customers off down a fork in the road! Our competitor continued to tell the story that they were more effective and their data was better but that no longer mattered. Efficacy was a “given” and the journey towards a better patient and physician outcome followed a new path requiring a package of services and support!

In the example above the “ticket to the ball park” was efficacy. If we had tried to compete or move away from this then we would never have won. However, by adopting a by-pass strategy, to move away from efficacy as the deciding factor we were able to win at our game! (incidentally we achieved a 49% share after 3 years against a business case, based on Zipff’s Law, that predicted a 30% peak share)

Note: We could also look at this in the context of Maslow’s hierarchy of needs. By moving customers “up” the pyramid we appealed to an “Esteem” need and showed them that their “Physiological” need (efficacy) was covered and giving more efficacy was not going to make them any more satisfied!

Changing the game is one way to “beat” Zipff’s law and the other is to move the customer base!

Moving the customer base!

Many years ago I worked for a health authority and had the unique experience of working with a clinical-effectiveness program which in many ways was a predecessor of the “value-based prescribing” model that the various governments have been trying to introduce nationally for a number of years. The most interesting thing about the model was that, for those who bought into the program their treatment options were managed by a “committee” of experts (not unlike NICE in the current environment) and funds managed by a “commissioning group” (yes CCGs existed long before the current UK reforms were announced!)

Traditional customers, the GP, were no longer making the decisions and once again share of voice or market entry position played no part in the choices being made by the experts.

In one case a market leading PPI was usurped by another based on the recommendation of the experts and the payors! The customer base had changed and the industry had not realised. (I was not very popular with the national sales manager of the company whose product had been displaced despite many years of support and heavy promotion to the local GPs!)

In the case above the customer base moved regardless of the industries intention, but just imagine if the you were able to move the customer base?

If your product truly is more cost effective with an infallible value story why would you focus your promotional efforts on prescribers? Why not work more closely with commissioners, HTA bodies, governments and health insurers?

For a product which offers a significant benefit for patients why not invest more into available DTC communication channels?

In the pharma business we will continue to see the prescriber making the decision to ‘buy’ however that decision is becoming increasingly influenced by other factors. Zipff’s law works well where those influences are minimal but as our ‘sale’ becomes more complex I do wonder how long Zipff’s law can be used as the gold standard in forecasting?

I am still a fan of Zipff’s Law and unless you are willing to take a risk to do something radically different it still provides an excellent tool for forecasting and resourcing. I suspect however that some companies will be surprised by what they see when competitors do start to implement more radical strategies and tactics!



About the author:

With 11 years in global marketing, an active imagination and a desire to continually question and challenge convention Chris Rose has worked in Sales and Marketing roles within the Pharmaceutical Industry leading the launches of primary care and specialty products.

Chris was previously employed by ProStrakan but is currently working as a consultant prior to starting in a new position with a new employer later this year.

How long can Zipff’s law be used as the gold standard in forecasting?