While NA estimates of average PC private consumption are closer to those in household survey compared to per capita GDP, the result are reversed when looking at growth rates. From 2003 to 2009, the average annual growth of per capita GDP was 1.6 percent, which closely aligns with the 2 percent estimated from household surveys (Table 9).

_Table 9: Average annual growth rate 2003-2009_

||**A**<br>|**verage Growth**<br>|<br>|
|---|---|---|---|
||**2003-2009**|**2003-2007**|**2007-2009**|
|**Per capita Consumption from household surveys**|-0.2%|-0.7%|0.4%|
|**Per capita GDP**|1.6%|1.8%|1.3%|
|**Per capita Private consumption from NA**|3.4%|2.0%|5.6%|

_Source_ : World Bank staff calculations, based on WDI and CBS data Pre-conflict data already revealed a substantial discrepancy between the growth-rate of per-capita welfare estimates based on NA private consumption and those coming from household surveys.<sup>23</sup> Over time, such discrepancy is expected to have further increased together with the deteriorating capacity of NA aggregates to reflect changes in the economy as a result of conflict. In particular, the likely increase of the informal economy as a result of conflict might have created an additional source of measurement error in available NA indicators. In principle, it could be assumed that an increase in informality would affect measurement error of GDP more compared to household final expenditure. However, as household final consumption expenditure in Syria’s NA is computed as a residual,<sup>24</sup> it could be assumed that the loss in reliability of growth estimates based on this aggregate is more severe than that based on GDP growth estimates.<sup>25</sup> Another important choice when identifying the growth rate in the per capita NA indicator to be used for poverty projections pertains the choice of the deflator. The general practice is to work with per capita NA aggregates expressed in constant terms using the GDP deflator, an implicit deflator that is meant to reflect price changes in goods and services purchased by consumers, businesses, government and foreigners (not importers). On the other hand, when assessing changes in consumption between household surveys collected at different points in time, the typical choice is that of using the Consumer Price Index (CPI), which measures the price changes in goods and services purchased by consumers (households). CPI is also used when expressing PPP conversion factors from 2011 or 2017 base years into the corresponding values in the years in which survey data are available for global poverty measurement. As shown in Figure 9, the GDP deflator and CPI trends, while generally aligned before conflict, diverge post 2011, possibly reflecting

> 23 El-Laithy, Aby-Ismail (2005). 24 Ibid.

25 Another element of concern regarding the reliability of Household and NPISHs Final Consumption Expenditure (HFCE) from NA pertains the lack of information on how its constant price estimates are computed by CBS. In fact, while GDP constant price estimates provided by CBS and included in WDI can be replicated using the GDP series in current prices and deflating it using the GDP deflator, the same does not hold in the case of HFCE. In fact, the constant price HFCE series provided by CBS and included in WDI cannot be replicated starting from the corresponding series in current prices neither using the GDP deflator (as it should) nor using the CPI. As CBS does not publish any documentation on the construction of the constant price HFCE series, the reliability of the metric is questionable.