Comparing cost against assumed effectiveness
In most cases the effectiveness of the newspaper advertising can only be gauged by the number of newspapers sold and multiplying it with the assume number that reads a single paper. When you buy a paper it is assumed that your whole household will read it so one paper can be calculated to be read by an average of about three people If the number is big then the cost may be seen as negligible thus effective.
Online advertising has come up with ways where they can tell a rough estimate of people who see you advert; you can be enticed to click on a link or a banner on promise of freebies, also they have counters for the visitors to the site where it is assumed the see the advert. But some publishers can manipulate the counter to cheat you on the visitors to their site. The cost of your advert should also be relative to the sites ranking on the several search engines.
Due to the multiple adverts in electronic outdoor advertising media the cost has come done. But it is very hard to tell directly the number of views per a certain period. The effect can only be felt if there is increased demand of you product. To make this more effective it should be combined with other methods and be place in relevant locations.
PPC advertising has come to solve the dispute between the advertiser and the advertising agent. You pay your advertisement based on the people who view it online. The advertising agent places your advertisement in many strategic sites where traffic is expected to be high and count the hits.