A trend is a description of the general direction of change in a physical, social, political, technological, or other system. Trends are based on the past behaviour of a system and assume that that behaviour will continue into the future.

Data supporting a trend may be quantitative (i.e. time series data), qualitative (i.e. a series of related events), or both. When writing trends, it is important to keep the trend statement (name) clear and simple. The trend statement should:

1. Identify the system or part of a system the trend is about.

2. What the direction of the trend is. For example, a good trend statement is “Global fertility rates are decreasing.”

When writing trend statements, avoid:

1. Compound trend statements. For example, “Global fertility rates are decreasing while population increases” should be entered into the database as two separate Trends.

2. Making a forecast instead of a trend statement. For example, “Global fertility rates are going to decrease in 2025” is a forecast or prediction about what will happen in the future and should be entered into the database as a Forecast.