DBMS_STATS.OBJECTTAB FOR SINGLE PARTITIONS

select * from v$version
BANNER                                                                          
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Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE    11.2.0.4.0  Production  
TNS for IBM/AIX RISC System/6000: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production

I'm looking to use DBMS_STATS.GATHER_DATABASE_STATS using the obj_filter_list parameter to gather stats on specific tables & partitions. I realise that Oracle can automatically gather stats and that this is often the best/most effective approach, but cleverer people than I have identified that we also need to add this capability to allow us to focus/specify stats gathering when required. The issue I'm having is that if I'm 'just' gathering stats on the table (using gather_database_stats), no issues, dbms_stats.gather_database_stats does its job as expected. However, when I add a partition name to the obj_filter_list, statistics are not gathered.