Do balances of opinion summarize at the best firms answers to business surveys?

Business surveys aim at getting, as quickly and as simply as possible, the recent and probable changes in economic activity. Answers to most of the questions are qualitative with three modalities (qualification of an evolution: up / stable / down). The qualitative indicators provided by these surveys are summed up in the form of balances of opinion equal to the difference between the percentage of answers in the upper modality and those in the lower one. However, such indicators do really summarise firms answers only if the percentage of answers to the modality stable are almost constant. The purpose of this paper is to sum up the answers to business surveys in a single indicator which takes into account the percentage of answers to the modality stable. This indicator is constructed from a principal component analysis which gives the linear combination of the three percentages capturing most variability between the sucessive surveys. Very close for some questions, the two summaries of answers appreciably diverge for other questions and can sometimes lead to a different short-term economic analysis.