I have a large dataset with longitudinal readings from single individuals. 
I want to summarise information over time into a binary variable. i.e. if diff in the input table below is >5 for any value I want to then reduce the observation for A to a new column saying TRUE. 

```
#Input

individual    val1    val2    diff
A    32    36    -4
A    36    28    8
A    28    26    2
A    26    26    0
B    65    64    1
B    58    59    -1
B    57    54    3
B    54    51    3

#Output

individual    newval
A    TRUE
B    FALSE

```