NEW YORK: Findings in the latest issue of the Journal of Advertising Research (JAR) offer advertisers some quantitative insights on one of marketing's most vexing – and longest standing – concerns: what is the ideal length of a television spot?

Spot Length and Unaided Recall in Television: Optimizing Media Planning Variables in Advertising Breaks examines the relationship between spot length and unaided recall in a real-world environment, and the direct effect on recall of other advertising break-planning variables.

These variables include the position of the break in relation to the television programme, the degree of advertising clutter in the break, the spot's relative position in the break, as well as primacy and recency effects. The research also examines the extent to which these variables moderate how spot length affects recall.

One top-line finding: "Longer spots – those lasting more than 20 seconds – generate more recall than would seem to correspond proportionally to the increase in length." This conclusion supports the argument that advertisers should buy longer spots to reduce the number of brands per advertising break.

And "given the greater recall resulting from lower levels of advertising clutter in a block," the JAR paper counsels, advertisers should seek to negotiate insertion of their longer spots in shorter advertising blocks.

"Television today faces competition from new forms of advertising media, as well as changing consumer habits. Nevertheless, because of its differential qualities with regard to other media, it still [has been] the leader in worldwide advertising investment," the authors write.

"But if television is to remain the number-one advertising format, it must strengthen its ability to help advertisers achieve their aims."

The authors of the study were Josefa D. Martín-Santana (Universidad de Las Palmas de Gran Canaria in the Spanish Canary Islands) and Pedro Reinares-Lara and Eva Reinares-Lara, both from Madrid's Universidad Rey Juan Carlos.

Data sourced from Journal of Advertising Research; additional content by Warc staff