TABLE 6.

Trend estimation for mathematics in Germany.

	Method	2003	2006	2009	2012	2015	Trend 2012 → 2015
							Est	SEtot	SEp	SEi
Original		503	504	513	514	506	−8	5.4	4.1	3.5
Without field test (all items)	C1	503	513	515	522	510	−12	5.8	3.0	5.0
	C2	503	515	517	524	511	−13	5.8	3.0	5.0
	H1	503	512	514	521	505	−16	6.0	4.2	4.2
	H2	503	517	521	528	515	−13	6.2	4.2	4.5
	S1	503	512	514	518	503	−15	6.1	4.2	4.4
Without field test (invariant items)	C1I	503	513	515	522	521	−1	5.8	3.0	5.0
	C2I	503	515	517	524	522	−2	5.8	3.0	5.0
	H1I	503	512	514	521	512	−9	6.4	4.2	4.8
	H2I	503	516	521	528	524	−4	7.0	4.2	5.6
With field test	C1F	503	512	515	516	518	2	5.8	3.0	5.0
	H1F	503	512	514	514	515	1	7.5	4.2	6.2
	S1F	503	512	514	518	517	−1	5.8	3.0	5.0

SE_tot = standard error due to sampling of persons and items; SE_p = standard error due to sampling of persons; SE_i = standard error due to sampling of items (link error).