From Davis’ description of slums, it can be inferred that slum research is challenging due to:
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* Language barriers that impede international interest for data collection in slum areas.
* The lack of variation in slum morphology (e.g. size, density, fragmentation, function, etc.)
* Little international interest in advancing a better understanding of slums.
* National governments disguising their poor and slum populations through misleading statistics.
* The evolving definition of slums that at one point encompassed moral dimensions that are difficult to measure.