While survey design and scale can address sampling error, the scale of the survey can paradoxically become the main source of non-sampling errors, such as those arising from non-response, coverage, measurement and processing. In particular, little is known about the bias resulting from non-response due to the respondent's incapacity to answer the questions. This paper attempts an assessment of the prevalence of such non-response errors across different categories of respondents. It evaluates the impact of these errors on estimation of monthly per capita consumption expenditure, using data from the 61st round of the National Sample Survey. Finally, it suggests alternative estimates for consumption expenditure as well as headcount ratios for poverty for selected major states, derived after eliminating the effect of non-response. The reliability of such estimates is also reported.