Advertising is an information war for winning attention and loyal attitude of consumers.  There is a formula that describes the advised level of expenditure on marketing: the desired market share multiplied by one and a half.  The result is the percentage of gross income to be spent.  Thus, if you wish to have 8% of the market, you will have to spend 12% of your sales revenues.

In this advertising war there is a special term, which is interference.  Interference is the concept that new advertising material presented after old advertising material has been learned interferes with the recall of the old material.

To achieve the expected effect from the advertisement it is vital to ensure frequent advertising exposure.  Target consumers remember the brands depending on how often they are reminded of them.  This is why in order for your advertisement not to be forgotten by consumers or replaced in their minds with something else you need to repeat it frequently enough.

There are three kinds of interference, proactive, retroactive and selective.  Let us take a look at them in turn.

Proactive interference means that consumers do not remember your advertisement well because they remember the ads of your competitors very well.  That is why when you introduce a new product to the market where your competitors have strong positions you must apply the maximum effort to overcome the barrier.

Advertising of new brands is not likely to be easily remembered and is forgotten more quickly than that of old existing brands, even if the frequency of exposure is the same.  The difference reaches 30%.  That is why when introducing a new product you have to increase the frequency of ads airing.

Retroactive interference is the result of massive competitors' attacks.  The frequency plays an important part in it, too.  After having conquered the target market share some advertisers make a mistake decreasing the number of the ads aired.  At this point the massive outflow of consumers may take place.  Some companies, like Procter & Gamble, use retrospective interference as a regular policy.

Selective interference is the absence or delay of consumers' reaction to the advertising caused by the flaws in ad design and/or content.  This kind of interference mostly originates from the unwillingness of an advertisers to evaluate the advertising from the customers' point of view.

In order to avoid all three types of interference it is crucial to know them well and understand their mechanisms, to perform different types of research before starting an advertising campaign and keep monitoring it in process.  As in any other war, winning takes strategy and planning.