Distributing print exposures through time

This article was published in the November 2004 issue of Admap.

Britain has a new tool to improve the planning of print media schedules – the National Readership Survey’s readership accumulation study, published in 2004. It provides estimates, publication by publication, of the rates at which the readership of individual issues of newspapers and consumer magazines build over time. A more realistic assessment can therefore be made of the day by day, or week by week, distribution of a print campaign’s audience.

The flighting of print and television ad exposures can be planned in the same way as each other, simultaneously. In effect, print can be treated like a broadcast medium as far as media scheduling is concerned. Campaigns can be planned with weekly target points, weekly reach estimates, and weekly weight goals.

Consequently the way publishers are viewing the survey is that the time has never been better for magazines and newspapers to capture a larger share of media-mix budgets.

Summary of method

The survey was conducted by NOP World, using NOP in London for the fieldwork and sister company MRI in New York for the editing and modelling. MRI had previously conducted an accumulation survey of its own in the USA, and obtained curves that were broadly similar to those found in Britain.

The sample of adults was recruited through the NOP Random Location Omnibus Survey. In a representative sub-sample of Omnibus interviews, respondents were asked to keep a diary of their reading of newspapers and magazines for one week. 70% agreed to do so. At the end of the week interviewers collected the completed diaries, or where it was not possible to collect them the diaries were posted back to NOP. Among those who agreed to participate, 60% successfully returned a usable diary. This amounted to 7,001 diaries.

Every day, for each publication read, respondents entered in the diaries the cover date of the issue as shown on the front page, indicated whether it was their own/household copy, and stated whether or not it was the first time that particular issue had been read. A sample page of the diary is reproduced in miniature on the right.

The completed diaries were shipped to New York for analysis by MRI. The diaries first went through an editing process in which logical consistency checks were made on the entries. There was no demographic weighting of the data, but weights were applied for primary and secondary readership, so that the profile of primary/secondary readership recorded for each title matched its NRS profile of primary/secondary readers.

The key measure was ‘first time reading’ (FTR) – that is, a reading event that the diarist recorded as being the first time he or she had read that particular issue. This measure was chosen by NRS because it logically fits the nature of NRS average-issue readership data. The main NRS survey only counts a reader once, regardless of how many times he or she picks up the same copy of a publication; and potential exposure to the advertising is delivered on the first time of reading. (QRS, the Quality of Reading Survey, suggests that approximately 70% of all pages are indeed opened on the first day of reading, on average.)

For every ‘first time reading’ event recorded in the diaries, the time-lag was calculated: that is, the number of days that had elapsed since that specific issue first became available. Consolidating these time-lags across all issues and all diaries produced the raw data for curve-fitting, by publication.

The diary data, being very different in kind from the standard NRS readership measures, were not intended to produce readership levels identical to those of the NRS in an absolute sense. Instead, the diary data simply had the objective of being a means of distributing through time the exposures which the NRS was reporting. Consequently the accumulation curves were designed so that on the vertical scale they eventually finished at 100%, where 100% is the NRS average-issue readership figure for a given publication.

The horizontal axis for the curves represented the number of days since the title first appeared. Day 1 was defined as the first appearance day. All curves started at day 1; any readership that occurred before then was allocated to day 1, for convenience. The axis extended to six months (day 181). Any curves which had not quite reached 100% by day 181 had the outstanding accumulation attributed to day 182+.

Curves plotted using the raw data inevitably showed some uneven-ness because of sampling variation on relatively modest sample sizes. Therefore MRI modelled accumulation curves for all publications and publication groups, thus smoothing out the bumpiness of the raw data, in order to produce curves which represent good predictions of future behaviour. The modelling used a number of different mathematical formulae, choosing the one that best fitted the raw data for each specific curve.

130 ‘first time reading’ events (FTRs) was set as the minimum sample size on which to base an accumulation curve. Any publication which achieved 130 or more FTRs would have a curve based solely on its own data. A publication with less than 130 FTRs would use all of its own FTRs and the shortfall below 130 would be made up by a contribution from the curve for the publication group to which it belonged (such as women’s weeklies or motoring monthlies). Any title with no FTRs of its own would simply use its group curve.

Examples of curves

NRS Ltd released 24 publication-group curves and 227 individual publication curves. I comment here on eight of the publication-group curves.

Daily newspapers accumulate their readers very quickly, as one would expect (see Chart A on the right, in miniature form). The average daily has reached 96% of a given issue’s readers on day 1, and another 3% catch up on day 2. Sunday newspapers are almost as quick, with 95% reached on day 1 and 99% by day 4, and newspaper supplements are not far behind.

TV weeklies are published several days before the listed programmes start, so there is a slight S-shape to the curve because most readers do not look at it until day 4 when 60% have accumulated. After that readership accumulates very fast as the viewing week covered by the programme listings starts. There are negligible new readers of the issue after the final day of the listings. Again, this makes complete sense.

General weekly magazines - titles such as Auto Express, The Economist, Country Life and New Musical Express – build up more slowly. 82% of readers see a given issue during week 1, and 91% have seen it by the end of week 2. The curve then almost flattens as pass-on readers take some time to be garnered, and after four months there are still 2% who have yet to see the issue.

Women’s weeklies accumulate their readers at a somewhat slower rate than general weeklies. 62% of readers see the issue in week 1, and 79% by the end of week 2. 91% are reached by week 5. After four months there are still 3% of an issue’s ultimate readers who have yet to see it.

As a generalisation, monthly magazines build up their readership more slowly than weeklies of course (see Chart B on the right). This is a combination of several factors including – typically - less time-critical content, a glossier and harder-wearing format, and more pass-on readers.

Women’s customer magazines, such as the Asda, Safeway and Somerfield titles, accumulate their readers relatively quickly for monthlies. Their method of distribution, editorial content, and relatively low readers-per-copy mean that by week 4 they have built up 81% of their readers, and 99% are reached by week 9.

Men’s monthlies – titles such as FHM, Men’s Health and Esquire – are the slowest-building category of all 24 publication groups, in the early weeks. By week 4 only 36% of readers have seen the issue. But the group maintains its rate of climb for a longer period than several other groups for whom diminishing returns set in more quickly. In week 9 men’s monthlies overtake the home interest group, and 90% of readers are accumulated by week 11. After six months there remain 5% of readers who have not yet seen a typical men’s monthly issue.

General monthlies accumulate their readers slightly more quickly than home interest monthlies. After six months 6% of general monthlies’ readers have yet to see the issue. For the home interest titles the figure is 9%, the highest percentage for any publication group. This reflects these magazines’ physical durability, the relatively timeless quality of the editorial content, their ability to remain desirable to future readers, and thus their comparatively high number of pass-on readers.

These eight examples give a general impression of how readership accumulates. They show how variable it can be from group to group, and how the variations make good sense. NRS subscribers have access to the entire database of course, which can be found on the subscriber-only section of the NRS website, www.nrs.co.uk. The full technical report can also be found there.

Using accumulation in media scheduling

The computer bureaux have written new software to handle the accumulation data, enabling users to input schedules insertion by insertion, and see the week-by-week print ratings and coverage, as well as summaries for the whole campaign. Insertions can be moved around and the effect on performance viewed, so that any weekly targets that have been set can be met as efficiently as possible. Campaign objectives can be achieved with improved effectiveness.

The exposures generated within specified parts of a campaign, such as during weeks of in-store promotions, can also be measured.

Some campaigns may have exposure continuing beyond the defined campaign period, at a low level, since a number of magazines have a tail of new readers who first see the title several months after the first-appearance date. It is possible to regard this as wastage but in most cases it is still delivering valuable exposure for the product. The accumulation data make it possible to assess for a given campaign period the extent and timing of any carry-over from the previous period – adding to the achievement in the current period.

I have little doubt that taking account of the time factor in this more precise way will eventually modify some aspects of the way that publications are generally used, particularly magazines. For example, in relatively short campaigns there will be a greater tendency to use monthly magazine issues which go on sale in the early stages of the campaign, while the later phases of the campaign will be oriented towards weeklies more than at present. The outcome will be an even more productive use of the medium.

If the campaign is using television as well as newspapers and magazines, the interlacing of the TV and print ratings can be explored and controlled. Planners and buyers will be able to synchronise with fine precision the flighting of print and television. This will highlight what some regard as the current under-utilisation of magazines and newspapers in mixed-media schedules.

There will be a new focus on a dilemma that faces planners who are using television and print in combination: should the two media run simultaneously, thus maximising the communication interaction between them – the ‘media multiplier effect’ – or should they run separately, so that the campaign period is extended? Either way, the accumulation data will enable the chosen strategy to be put into effect more productively.

The new data will also spur media buyers to increase their dialogue with their strategic planning colleagues.

Demonstrating print’s return on investment

Another benefit of the new accumulation data is that the link between media exposure and sales can be investigated more accurately. There have been a number of studies in the past which have used household purchasing panels to demonstrate that newspaper or magazine advertising created sales and gave a positive return on the investment. This has involved comparing the timing of the sales with the timing of the readership created by the campaign, and showing a link.

Unfortunately the link was made fuzzy by the implicit assumption behind the readership figures that all the ad exposures occurred in the week in which the issue appeared. Since the new accumulation data will enable such studies to spread the ad exposures through time in a much more realistic way, the link between exposure and purchase should be revealed as being even closer than previously measured.

Footnote

Admap is a monthly journal devoted to making advertising, marketing and research more effective (visit www.warc.com). The above is the unedited version of the article, slightly modified to appear on this website.