Convert-Me.Com - online units conversion

Is there a correlation between the watt, (power) and the lumen,(illumination)? It's confusing to try to determinewhich flashlightoffers more light when they're listed in watts and or lumens.

Every source of light has different ratio lumen/watts (sometimes quoted by manufacturer in their specifications). For incandescent lamp it is approx. 12-14, for halogen could be over 30 but a broad range , for luminescent over 50 for LCD even higher, therefore the Q ?is to define well the source and research about the ratio.