is an audience measurement term that identifies the percentage of
television households with sets in use which are viewing a particular
program during a given time period. If the total TV audience is
represented by a pie, the audience for each program is a slice or
share of that pie. The slices are not equal, however, since audience
share varies widely according to the relative popularity of each
program. Share is a comparative tool; it allows station and network
executives to determine how well their programs are doing when compared
with competing programs on other broadcast or cable channels.
Share is closely associated with rating, another measurement term.
Both terms are derived from the same estimates of audience size,
but the percentage quotient is calculated differently. Share measures
the percentage of TV viewers who are actually watching a particular
program, while the rating for a program calculates the percentage
of all television households--both those using TV and those
not using TV.
example, station WXXX airs Jeopardy at 7 p.m. Sample data estimate
that 10,000 or 10 percent of the city's 100,000 TV households are
viewing that program. Some 40,000 households are viewing other programs,
but another 50,000 are not using their TV sets. Since 10,000 of
the 50,000 active viewers (20%) are watching Jeopardy!, that
program has a share of 20 even though its rating (the percentage
of TV households) is only 10.
media trade journals generally report both rating and share. Rating
is expressed first and is given to the nearest tenth of a percent.
Share follows and is rounded to the nearest whole percent. For example,
an audience estimate for 60 Minutes may report a 13.0/28;
i.e., 13% of the total TV households (the rating) and 28% of the
viewing audience (the share).
If every television household was using TV during a given time period,
the share and the rating would be equal. But since this never happens,
the share for any program is always greater than its rating because
different divisors are used to calculate the two equations.
gap between share and rating is greatest during periods of very
light viewing. An early morning newscast with a share of 30 and
a rating of only 3 is competing very well against other programs
in the same time block even though the total number of viewers for
all programs is small.
is useful as a comparative tool during virtually any portion of
the day, however. When a program gains share, it usually does so
at the expense of competing programs since the total audience for
television during any given day-part is relatively stable.
can also be used to illustrate programming trends. One network may
average its share of successive programs to illustrate its dominance
on a particular weekday night. A new broadcast or cable network
may average its share across an entire season to illustrate its
increasingly competitive position over a previous season.
can be used to demonstrate industry trends. For example, the combined
share of ABC, CBS, and NBC for the 1980-81 programming year was
90. This meant that 90% of the viewing audience was watching one
of these three networks. The remaining 10% of the audience was distributed
among independent stations, public television, and the few cable
networks then operation. By 1993-94, combined network share had
dropped to 60, primarily because the cable networks collectively
had captured one-third of the network viewers. Some industry observers
predict that network share will continue to decline; others believe
the erosion of network share has been halted and possibly reversed.
A study of network share measures the competition between traditional
broadcasters and their new technology competitors.
otherwise specified, share refers to the total universe of television
households. Share can be used in demographics breakouts, however.
A morning talk show may have a 2.2/20 for women 18 to 34 years of
age. That would be the rating and share for this particular demographic
Hugh Malcolm. Audience Ratings: Radio, Television, and Cable.
Hillsdale, New Jersey: L. Erlbaum, 1988.
Roland T. and Naras V. Eechambadi. "Scheduling Network Television
Programs: A Heuristic Audience Flow Approach to Maximizing Audience
Share." Journal of Advertising (Provo, Utah), Spring 1989.
James C. and Lawrence W. Lichty. Ratings Analysis: Theory and
Practice. Hillsdale, New Jersey: L. Erlbaum, 1992.
also A.C. Nielsen
Research, Industry and Market Approaches; Cost-Per-Thousand;