# Thread: Need a term for a trend

1. ## Need a term for a trend

Sorry, this is a basic question. I'm looking for a term which describes the following kind of trend.

Let's say a value in a time series peaks at a rate of 100 in the third year. The rates during the build-up phase are 50 in Year 2 and 25 in Year 1. In other words, during the build-up up to and including the first year of the peak, a predecessor is always half of its successor.

I'd be grateful for any help.

2. Originally Posted by lingyai
Sorry, this is a basic question. I'm looking for a term which describes the following kind of trend.

Let's say a value in a time series peaks at a rate of 100 in the third year. The rates during the build-up phase are 50 in Year 2 and 25 in Year 1. In other words, during the build-up up to and including the first year of the peak, a predecessor is always half of its successor.

I'd be grateful for any help.
Exponential trend or growth

RonL

3. Thanks. But is there a way to describe this trend of doubling rates up to and including the build-up have a special name -- in other words, is there a more succinct way to describe it than in my original post?

4. Originally Posted by lingyai
Thanks. But is there a way to describe this trend of doubling rates up to and including the build-up have a special name -- in other words, is there a more succinct way to describe it than in my original post?
Exponential growth with a doubling period of 1 year from an initial value of 25.

RonL

5. Originally Posted by lingyai
Sorry, this is a basic question. I'm looking for a term which describes the following kind of trend.

Let's say a value in a time series peaks at a rate of 100 in the third year. The rates during the build-up phase are 50 in Year 2 and 25 in Year 1. In other words, during the build-up up to and including the first year of the peak, a predecessor is always half of its successor.

I'd be grateful for any help.
Geometric progression. Or, geometric sequence.

The common ratio between two progressing, successive terms is 2.
y1 = 25
y2 = 50
y3 = 100
.
.

---------------
y2/y1 = 50/25 = 2
y3/y2 = 100/50 = 2
.
.