NRS - SAMPLE VARIATION
NRS obtains its readership estimates by interviewing a representative sample of the population. NRS interviews some 3,000 people every month of every year, but despite having a large, high-quality sample, NRS estimates, like any estimates obtained from a sample, are subject to sample variation. This is not a factor for ABC which is not a survey but an audit. Sample variation is a function of the fact that samples are very rarely a perfect representation of the populations they are designed to represent, and although weighting can be used to correct the data, some variations between one period and another are unavoidable. The degree to which sample variation alone is responsible for period-on-period differences in the readership estimate for a given title can be demonstrated by what is known as significance testing. If the test shows the difference is significant, it is almost certain that it is a reflection of a real change in readership. If on the other hand the difference is not significant, the difference may be due simply to sample variation and not to any real change in reading behaviour.
NRS - METHODOLOGICAL FACTORS
NRS strives as far as possible for consistency over time in its methodology, in terms of the selection of the sample, the procedures used to weight the data, and the interview itself. However, the Survey is also committed to innovation and improvement, and from time to time one-off changes are introduced that could affect the level of readership claims, and therefore RPC, and in such cases it is possible that not all titles would be affected to the same extent.
ABC
ABC is a reliable measure of the average number of copies per issue that are distributed. However, there are differences between ABC and NRS reporting that can affect RPC. For example, NRS estimates are based on a survey universe of Great Britain (i.e. England, Wales and Scotland, but not Northern Ireland or Eire). ABC, on the other hand, does not report circulation for Great Britain. In the case of newspapers, ABC breaks out Total UK (i.e. Great Britain and Northern Ireland), England/Wales/Northern Ireland combined, and Scotland only; in the case of magazines, it reports Total UK and Eire combined. |
Various studies have shown that many year-on-year changes in RPC are statistically significant - in other words, they are a reflection of a real change in the relationship between readership and circulation, and not simply a function of sample variation. There are a large number and variety of factors that can contribute to real changes in RPC, and a number of these are summarised below. These factors do not necessarily operate in isolation, but can be inter-connected, and one can counter another, so it is often difficult to identify and quantify with any certainty why the RPC of a particular newspaper or magazine has changed over time.
SOURCE OF COPY
The way in which copies are obtained, and how they subsequently move about, is a key determinant of RPC. In principle, copies which are first read in-home, and stay there until they are disposed of, accrue fewer pass-on-readers (and therefore have a lower RPC) than copies that are passed on to other households, or those that are circulated in workplaces or displayed in other public places. Past studies have shown that copies of publications displayed in public places can generate 20 or more RPC. Certain actions by publishers concerning the distribution of copies can therefore affect the level of RPC. For example promoting the circulation of copies in workplaces or hairdressers could lead to an increase in RPC.
CHANGES TO THE PUBLICATION
Changes to the format or editorial content of a publication can affect its RPC. These changes can be slow and evolutionary, or, as in the case of a major relaunch, more dramatic. In the latter case, it is often associated with heavy promotion of the title. The effect on RPC can go in either direction: a major relaunch could be akin to the launch of a new title (see (e) below) in which case readership might not keep up with increases in circulation, and RPC would therefore fall. On the other hand, changes to format or content could broaden the appeal of the publication thus increasing the level of pass-on readership, in which case RPC can increase.
SHORT-TERM FLUCTUATIONS
In addition to long-term planned changes by publishers, short-term fluctuations in circulation and readership can occur, and these can be of sufficient magnitude to be reflected in RPC. For example, major news items can increase circulation and readership of newspapers but if the two are not affected equally, RPC could go up or down temporarily. Similarly, the sales of certain magazines are heavily influenced by promotions such as cover-mounted gifts: an attractive promotion can substantially increase sales of a particular issue, but this does not automatically translate into an equivalent uplift in readership.
SEASONALITY
Some titles have pronounced seasonal peaks and troughs in readership and circulation. For example, interest in gardening titles is greater in the spring and summer than it is in autumn and winter. Such seasonal fluctuations do not always affect circulation and readership to the same degree, and RPC can therefore rise and fall throughout the year.
NEW TITLES
A newly-launched publication usually has a lower initial RPC than the figure it eventually achieves after 3-4 years. One reason is that a network of pass-on readership can take some time to be developed, in which case RPC of a new title starts low and slowly rises over time, and this implies that the NRS estimate is a good indication of what is actually happening. A separate possibility is that because some new titles may take time to establish themselves in the public consciousness, a proportion of NRS respondents who have read such a title might not recall the title in the NRS interview, in which circumstances NRS could to some extent be under-estimating readership. Over time, as readers become more familiar with the title, the readership estimate - and RPC - can increase.
COMPETITION FROM OTHER TITLES
The launch of a new title can have an impact on the RPC of existing titles by affecting circulation or readership or both. For example, if pass-on readers of a title (i.e. those who do not buy or acquire it themselves) are lured away by the arrival of a new title, the circulation of the existing title might not necessarily be affected, but its readership, and consequently its RPC, could decline. Changes in editorial format and content of one title can also have an impact on the circulation or readership of its competitors. When a title closes, this can also affect other titles, insofar as readers of the closed publication migrate to other publications.
INCREASES IN CIRCULATION TEND TO REDUCE RPC
When circulation of a title is growing, it is often the case that readership does not grow at a similar pace. As is the case for new titles, someone who has only recently started to regularly buy a publication will generally generate fewer pass-on readers than established purchasers. Moreover, if the growth in circulation comes from people who were themselves previously readers of someone else’s copy, not only does this mean that new readers are not being generated, but previous pass-on readers are being lost. An example of the latter might be a title whose circulation has been boosted by the success of a subscription programme: if a proportion of those taking up the subscription offer were existing pass-on readers, circulation would increase but readership would not, and therefore RPC would fall.
FREE COPIES
Copies of a publication that are free tend to generate fewer pass-on readers than copies that are paid for, because a person picking up or being handed a publication for free may dispose of it sooner than if they had paid for it. This may also be true, but to a lesser degree, in circumstances where copies are sold for substantially less than the full cover price.
READERSHIP LAG
In some cases, readership follows the same general trend as circulation, but lags behind it. Circulation of a title might increase, but readership stays level for a time. Conversely, the reverse might occur: circulation starts to fall, but again readership remains level for a time. Such lags can occur because publications can continue to generate readers long after their publication date; this is more likely to occur with magazines than with newspapers, and within magazines it is more likely to affect those titles with a long active life. The varying average-issue lifetime of publications was amply demonstrated by the NRS Survey of Readership Accumulation over Time (for more information on Readership Accumulation, click here).
MULTI-PLATFORM DEVELOPMENT
Many publishers have invested in extensions of their printed titles using different platforms, the aim being to increase the contact existing readers have with their publication brands, and to attract new customers. Thus far, the most heavily developed platform is websites. Websites offer an alternative means of accessing editorial content, and this could have an impact on circulation and readership of the print versions. Those who purchase the publication can use both - print and website - but if former pass-on readers of a print title now only use the website, this will result in a fall in RPC for the print title concerned.
HOUSEHOLD SIZE
Household size can have a strong influence on RPC, particularly for the types of publication that tend to stay in the home. There has been a long-term trend towards a greater number of smaller households, and this may have contributed to a long-term general reduction in the RPC of newspapers and magazines.
DEMOGRAPHIC CHANGES
Changes in the make-up of the population can affect the circulation and readership of some types of publication more than others. Between 1997 and 2007, the adult population is estimated (by the Office of National Statistics) to have grown by 5% overall, but this growth was not evenly distributed by age. For example, the number of 15-24 year-olds increased by 12%, and the number of 55-64 year-olds by 25%, whereas 25-34 year-olds declined by 16%. The increase in 15-24 year-olds has increased the potential pool of readers for youth-orientated titles, but this has to a degree been offset by an underlying decline in reading newspapers and magazines by this age group. The increase in the 55-64 year-olds has created new opportunities for publishers, but this age group tends to live in smaller households, and therefore the potential for generating additional RPC is somewhat less. Titles with an ageing readership might be expected to show a decline in RPC.
SOCIAL FACTORS
In addition to demographic factors, there are some social changes that can affect the readership and circulation of some publications. For example, the increasing affluence of the population, and the tendency towards greater discretionary spending, could mean that people are in general more able and willing to buy a magazine or newspaper themselves rather than reading someone else’s copy, and this would have the effect of reducing RPC. It will be interesting to observe what effect the current recession has on this trend. It has also been commented that neighbourhood and extended-family communities are becoming less cohesive, and this again could have an impact on RPC by reducing the level of pass-on readership. |