This is from a Schweser question. Full replication is given as least likely in case of equal weighted index compared to other index weighting methods. The reason is stated as the bias towards small cap stocks and illiquidity of these stocks. I gave this answer thinking about rebalancing. I thought rebalancing with a equal weighted index will be too often as return differential between the index components will cause a drift and hence a need to rebalance quite often. Is this line of thinking relevant for determining the choice of indexing?
I think they mean the same thing. Equal wt index consists of a large proportion (in #) of small cap stocks, which typically have low liquidity (since they may not be popular). So trying to replicate this would involve significant volume of rebalancing which translates to higher cost. I think the key point to highlight is bias towards small cap stocks for equal wt index. - BN