The phrase "admittedly arbitrary" is correct and usable in written English.
It can be used when acknowledging that a decision or choice is based on personal judgment rather than objective criteria.
Example: "The criteria for selecting the winner were admittedly arbitrary, as we simply chose the entry that resonated with us the most."
Alternatives: "undeniably subjective" or "clearly random".
Setting the sample two years in the past as opposed to one or three years is admittedly arbitrary.
While setting the date to January 1st, 2007 is admittedly arbitrary, there really is no fairer way of choosing the date and therefore is not worthy of extensive debate.
Only four of the European members currently spend at least two percent of GDP on the military, NATO's admittedly arbitrary standard.
Pew uses an admittedly arbitrary but reasonable measure: households with between two-thirds and two times the median income, which amounts to about $40-120K 40-120K dollars.
Ohio and Iowa are currently labeled as "tossups" on the HuffPost Election Dashboard map, for example, because Obama's margins there have fallen below the admittedly arbitrary cut-off of 2.5 percentage points, a range within which the final polling averages have sometimes erred.
While our decision rules are admittedly arbitrary, they are derived from common GIS analysis for site selection in the energy industry, and we believe any reasonable set of decision rules would provide qualitatively similar results.
As such, I decided to look at two different — and admittedly slightly arbitrary — measures of success.
The categorization used here is admittedly somewhat arbitrary (some "lobs," for example, are also "pick-and-roll assists to the roll man"), but mainly meant to showcase just how wide-ranging and proficient Morris' passing acumen is.
We chose to report the results for out-going links following the intuition that the role as an information producer is more relevant than the role as a receiver - admittedly an arbitrary decision, which ought to be interpreted as an additional reason for us to develop a method that integrates in- and out-connectivity in a more meaningful way.
It is not clear whether it is preferable to use a weighted network, in which all edges are present but of variable magnitude, or an unweighted network, with an admittedly somewhat arbitrary threshold for placing an edge.
Though no direct correlation can be suggested, it is nevertheless striking that the number of catalytic functions necessary to close the system (admittedly under somewhat arbitrary conditions) approximates the number of genes in a simple eukaryote.
