# Thread: Formula to find similar values and report difference in years

1. ## Formula to find similar values and report difference in years

Hey everyone,

I hope you can help me out. Here is the problem:

If you look at the excel file you can see a lot of countries and years starting from 1960 till 2008. The third column indicates the intensity of computer use per country per year. It is reasonable that a lot of data is missing in the first decade(s), simply because the computer is something relatively knew. In the complete dataset more technologies are present and these may be available from the 1960’s onwards (for example telephones).

Using this data I want to calculate the years lag between the United States and country X, where country X is every single other country stated in the dataset. This lag can be explained as the difference in time between a country’s technology usage intensity (so country X) and the last time the United States had a similar technology usage intensity.

To give an example:
When looking at Austria, the year 1998 and the computer usage intensity (see cell C138 = 0.23342137), it can be obtained that the United States had a similar computer usage intensity in 1991 (see cell C4054 = 0.233614376). The formula then reports that the lag is 7 years (=1998 – 1991).

Of course it might be the case that for some countries and years there cannot be an answer.

To illustrate that I will give another example:
When looking at Argentina, the years 1988 and the computer usage intensity (see cell C30 = 0.004405223), it can be obtained that the United States had NOT a similar usage intensity in the history. The United States had in 1981 a computer usage intensity of 0.009218756, but this is much higher than the computer usage intensity of Argentina in 1988. So the formula should report either an error or just state a dot as to indicate it cannot be calculated. This illustrates directly that the computer usage intensity of country X for a given year should be larger than or equal to (>=) the computer usage intensity of the USA in some year.

If you have any questions, please state them below!

I hope you all have an idea what the formula should look like.