DeckArray Leftover Rows

When using unedited variables as parameters of your DeckArray, it may be useful to include a "leftover" (spillover) row for cases in which the variable is not valid. This functionality allows the user to simulate the use of many hotdecks using a single array. An example will best explain this functionality.

This following is a hotdeck for housing type, based on the source of drinking water (H8), the type of toilet (H9), and whether or not the household has electricity (H10).

	    array
	 housingTypeHD(H8_VS1(+),H9_VS1(+),H10_VS1(+)) save;

At the point that housing type, H6, is edited, none of the dependent variables in the hotdeck have been edited, so the values can be blank or invalid. That is why, in the array definition, a (+) has been added after the value set names. The (+) gives an extra row for any value that is not in the value set.

When updating the hotdeck in cases where the housing type value is valid, adding a (+) after the DeckArray name will update the "leftover" rows.

	    putdeck(housingTypeHD(+),H6);

This means that when the hotdeck is called upon for an edit or imputation, having valid values for H8, H9, or H10 is not necessary to return a valid H6 value. This fundamentally makes the housing type DeckArray eight hotdecks combined into one. The table below explains what happens when executing a getdeck function call:

	    impute(H6,getdeck(housingTypeHD));
	 

H8	H9	H10	Take the H6 value from the nearest neighbor with the same values for...
Valid	Valid	Valid	H8, H9, and H10
Valid	Valid	Invalid	H8 and H9
Valid	Invalid	Valid	H8 and H10
Valid	Invalid	Invalid	H8 only
Invalid	Valid	Valid	H9 and H10
Invalid	Valid	Invalid	H9 only
Invalid	Invalid	Valid	H10 only
Invalid	Invalid	Invalid	The previous valid household's value

Or in words:

If electricity is blank, use a hotdeck based on water and toilet.
If electricity and water are blank, use a hotdeck based on toilet.
If water is blank, use a hotdeck based on electricity and toilet.
If all three are blank, use a hotdeck based on the previous valid household.
Etc.