Chinese patents data coverage in PATSTAT

Following my recent post about chinese patents data, I had a a deeper look into SIPO (chinese patent office) and organized data by year (see table below) and compared them against PATSTAT 10/2009 data.
We can understand that, leaving aside designs, that data coverage is usually over 90% on applied patents.

Year	Total	Inv + utility	Invention	Utility Model	Design	PATSTAT	% coverage
1985	14.372	13.732	8.558	5.174	640	12.532	91,26
1986	18.509	17.682	8.009	9.673	827	15.992	90,44
1987	26.077	24.765	8.059	16.706	1.312	22.411	90,49
1988	34.011	32.052	9.652	22.400	1.959	27.388	85,45
1989	32.905	30.386	9.659	20.727	2.519	27.215	89,56
1990	41.469	37.752	10.137	27.615	3.717	32.090	85,00
1991	50.040	44.705	11.423	33.282	5.335	37.713	84,36
1992	67.135	58.778	14.409	44.369	8.357	48.832	83,08
1993	77.276	67.117	19.618	47.499	10.159	54.916	81,82
1994	77.735	64.578	19.067	45.511	13.157	57.315	88,75
1995	83.045	65.377	21.636	43.741	17.668	60.224	92,12
1996	102.735	78.121	28.517	49.604	24.614	67.837	86,84
1997	114.208	83.795	33.666	50.129	30.413	73.285	87,46
1998	121.989	87.357	35.960	51.397	34.632	79.939	91,51
1999	134.239	94.186	36.694	57.492	40.053	91.110	96,73
2000	170.682	120.562	51.747	68.815	50.120	112.283	93,13
2001	203.573	142.926	63.204	79.722	60.647	132.884	92,97
2002	252.631	173.371	80.232	93.139	79.260	165.357	95,38
2003	308.487	214.433	105.318	109.115	94.054	204.918	95,56
2004	353.807	242.958	130.133	112.825	110.849	234.252	96,42
2005	476.264	312.893	173.327	139.566	163.371	286.538	91,58
2006	573.178	371.856	210.490	161.366	201.322	337.228	90,69
2007	693.917	426.485	245.161	181.324	267.432	354.732	83,18
2008	828.328	515.424	289.838	225.586	312.904	255.837	49,64

The delusion comes from the quality of data coverage...

When examining the applicants data out of 776607 applicant none has a zip code or a city.
Only 3161 have an address (where address city zip are packed altogether) but all of them are non-chinese.
So no geographic analisys is possible.

One more thing to be careful about are counts by publication numbers: FI if you look for patent # CN1237182  you will find 2 different patents: the first with status A (unexamined) and the latter with status C (granted).

So we should clarify the meaning of Publication number. According to SIPO, there is more than one kind of publication numbers which are reflected by the Kind Code:

  ‘A’: Publication of Unexamined application for patent for invention

  ‘C’: Publication of Granted patent for Invention

‘Y’: Publication of Granted patent for Utility Model

‘D’: Publication of Granted patent for Design

Last but not least: IPCs.

Out of 3.270.000 published patents 1.136.000 have no indication of primary ipc class.

So we're going to use data straight from SIPO to build a chinese patents database...

(bytheway, if you are willing to search into sipo website, this is the link to english search page:
http://218.240.13.210/sipo_EN/search/tabSearch.do?method=init )