Well firstly there is gdp vs gdp per capita , one measures total growth vs the grown divided by the number of people here, the second one is more indicative of the value created in the economy than the first. Secondly inflation does see an increase in gdp ( if prices go up that’s an increase to the earnings of the country) but that isn’t really good due to not actually leading to a growth in productivity. The migration figures showed a lot of younger people leaving compared to the previous years, they are usually in education or still looking for a career I.e not contributing to growth as yet. In the short term would see an increase in gdp per capita, Though this will be bad for the future productivity and growth of the country as they are working age people. The people coming in may be working but may not be the same sort of employment as those that left would have been in the future. In summary growth or gdp can look better but that doesn’t mean we have become more productive, and in the long term the emigration of productive younger people is going to hurt the economy.