Trend analysis (trend extrapolation) is a forecasting method based on identifying, based on historical data and observations, an ongoing change. The point of trend analysis is to identify the trend early, while it is still likely to continue in the future.
Quantitative trend analysis deals mostly with data as opposed to information. Statistics pertaining to the subject are gathered and plotted along a time axis to produce a curve, which can be extrapolated into the future. An example of a quantitative trend is Moore's law, improved fuel efficiency of cars, the annual number of transplants and the number of cybernetically enhanced humans.
Of course, the further in time the extrapolation, the greater the uncertainty of the event happening and there is no guarantee that the variable will continue to change the way it did in the past. This kind of trend analysis is normally used to draw attention to the forces that could change the extrapolated pattern. More sophisticated analysis (e.g. time series analysis) can be used to try to reveal different patterns.
Trend analysis can also be used to identify qualitative trends, where the quantitative data cannot be obtained (example: globalisation). Characterising such trends requires creative and systemic thinking and is one of the most challenging aspects of futures research.
Trends come in different sizes. A mega-trend extends over many generations, and in cases of climate, mega-trends can cover periods prior to human existence. They describe complex interactions between many factors. The increase in population from the palaeolithic period to the present provides an example of a mega-trend.
Possible new trends (or "trend babies") grow from innovations, projects, beliefs or actions that have the potential to grow and eventually go mainstream in the future (for example: just a few years ago, alternative medicine remained truly "alternative". Now it has links with big business and has achieved a degree of respectability in some circles and even in the marketplace).
Very often, trends relate to one another the same way in which a tree-trunk relate to branches and twigs. For example, a well-documented movement toward equality between men and women might represent a branch trend. The trend toward a minimizing differences in the relationship between the salaries of men and women in the Western world could form a twig on that branch.
Life-cycle of a trend
When does a "trend baby" gain acceptance as a bona fide trend? When it gets enough confirmation in the various media, surveys or questionnaires to show it has an increasingly accepted value, behavior or technology. Trends can also gain confirmation by the existence of other trends perceived as springing from the same branch. Some commentators claim that when 15% to 25% of a given population integrates an innovation, project, belief or action into their daily life then a trend becomes "mainstream".