Jordan Kyle 
'V' graphs 
‘V’ graphs plot coefficients and standard errors from separate regressions on different panels of data. They are ideal for cases when you expect the coefficient of an independent variable to either operate in opposite directions for separate panels or when you expect the coefficients to be insignificant for particular panels.

The dotted line represents the ratio between coefficient size and standard error required for 95% statistical significance (1/1.96). Therefore, all points beneath the dotted line are statistically significant, and all points above the dotted line (inside the 'V') are not significant at the 95% level. To the extent that points cluster in one region of the graph, we can have greater confidence that a pooled model is appropriate. For example, we find consistently positive and significant associations between donor fragmentation and aid fragmentation: 
R code to run separate regressions over different panels and store the coefficients and standard errors from each regression, then to produce the 'V' graphs can be found here. The code has been generalized to so that it can easily be used for any dataset. STATA code to produce the 'V' graphs can be found here (STATA version does not include the code for the loop that stores coefficients and standard errors). Specific code to produce the graphs shown here can be provided upon request.
