The totality of the given conditions is referred to as a panel effect, die zu einer Beeinträchtigung der Aussagekraft des Panels führen. Der Paneleffekt tritt beim Household panel auf, nicht hingegen bei unternehmensbezogenen Panels, z. B. dem Einzelhandelspanel. Er kann umfassen:
The participants in the household panel are exposed to learning and awareness processes that can more or less consciously lead to artificial changes in purchasing behavior.
The ongoing documentation of purchases draws attention to one's own purchasing behavior and brings it to the fore. Since panelists have to keep a record of their purchases, they better prepare them and refrain from making spontaneous purchases.
The panel members are buying new articles to a greater extent, which can be traced back to the communication of appropriate suggestions through the forms.
The specification of certain products is also the cause of overreporting as increased reporting. If someone has not procured a certain good for a long time, then this is sometimes not compatible with his sense of prestige, which is why purchases are indicated that were not actually made. The reasons for increased reporting can, however, also lie in the anticipation of acquisitions or in covering a pent-up demand.
The participants in the household panel suffer from signs of fatigue over time. What was initially perceived as interesting, later appears annoying. Purchases are not, incorrectly or incompletely recorded due to negligence or forgetfulness. There is underreporting, ie reduced reporting.
Um den Paneleffekt und zugleich die Panel mortality zu beeinflussen, wird z. B. jährlich ein Drittel der Panelteilnehmer durch neuangeworbene Haushalte ersetzt.
Panel effect - after a certain period of time, panel participants can become more self-observing and become more aware of their shopping behavior, such as more conscious shopping or more interest in new products. The panels are therefore constantly being refreshed by new households that move up, which, however, are only included in the panel after a start-up period.