Sentence:  The early models of famine early warning systems adopted the approach of gathering all possible (or measurable) indicators, adding them up and deducing vulnerability. This was termed the <WSD>hoovering</WSD> approach—vulnerability was the weight of the bag after vacuuming up everything in sight (<WSD>hoovering</WSD> is the British word for vacuuming). 
Meaning of the word marked with <WSD> tags:  To suck in or inhale, as if by a vacuum cleaner.