Identification of Keywords for Legal Documents Categories Using SOM

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Comparison of accuracy between the NER model and Polish RoBERTa in each category of document

Category	RoBERTa [%]	NER [%]
Civil law	68.88	72.00
Administrative law	31.40	55.73
Pharmaceutical law	67.80	74.36
Labor law	62.88	59.15
Medical law	65.56	77.05
Criminal law	55.77	62.22
International law	0.00	35.29
Tax law	12.77	77.27
Constitutional law	13.33	50.00

Number of words in each category with different thresholds of acceptance for how unique a keyword must be to a category_

Category	Share of words
	>50%	>90%	100%
Civil law	587	470	466
Administrative law	209	192	191
Pharmaceutical law	253	210	210
Labor law	358	264	263
Medical law	834	599	595
Criminal law	105	90	89
International law	14	12	12
Tax law	42	34	34
Constitutional law	2	2	2
Total	2,404	1,873	1,862

Coherence (C) and descriptiveness (D) of classes using RoBERTa embeddings_

Category		C	D
Civil law	231	0.6	0.055
Administrative law	151	0.53	0.08
Pharmaceutical law	298	0.68	0.048
Labor law	583	0.6	0.023
Medical law	994	0.59	0.027
Criminal law	20	0.53	0.235
International law	137	0.61	0.076
Tax law	25	0.45	0.195
Constitutional law	280	0.64	0.056

Number of words in each category during each step of data preparation

Category	Before	Step 1	Step 2	Result
Civil law	10787	2764	1023	470
Administrative law	5182	1786	562	192
Pharmaceutical law	4742	1489	558	210
Labor law	9707	2081	828	264
Medical law	17503	3447	1407	599
Criminal law	4579	1347	418	90
International law	374	199	40	12
Tax law	1197	468	145	34
Constitutional law	73	40	6	2
Total	54,144	13,621	4,987	1,873

Number, coherence and descriptiveness of documents before and after using exclusively strong keywords

Category	Before changes			After changes
	Number of documents	Coherence score	Descriptiveness score	Number of documents	Coherence score	Descriptiveness score
Civil law	863	0.51	0.031	223	0.74	0.041
Administrative law	164	0.85	0.054	84	0.85	0.062
Pharmaceutical law	212	0.79	0.043	101	0.8	0.064
Labor law	327	0.79	0.043	154	0.84	0.055
Medical law	846	0.68	0.023	377	0.71	0.034
Criminal law	192	0.82	0.288	78	0.83	0.325
International law	7	0.94	0.09	3	0.95	0.123
Tax law	61	0.9	0.577	34	0.89	0.550
Constitutional law	2	1	0.038	2	1.00	0.066
Sum	4,402			1,056