What does it mean when you say "The fundamentals of the economy are strong". What are the fundamentals?

Question

More specifically I'm curious what metrics were used to quantify the economy being "strong".

Answer 1

PPI, CPI, other inflation indicators

GDP, GDI

Imports, Exports, dollar value

Answer 2

When politicians say it it means   things are bad, and will probably get worse, but I hope you don;t notice until I leave office. Economist are more likely to say fundamentals are weak  which they are now. Government  deficits, savings rates , company profits, productivity, job growth,  stability of the Banking system. inflation rates are all indicators of future  growth of GDP rate.