There are several connexions between these stories, both thematic and lexical. In both stories an oath is made forbidding an action, and then someone breaks that oath. I find it significant that the person who breaks the oath is NOT the person who actually took the oath. To what extent is an oath binding on someone who has not taken that oath? In both cases the person who takes the oath is a leader of the Israelites, which presumably gives it authority. Again I wonder why the oath would be binding on Jonathan who was not even aware of it.
In both stories, the Israelites suffer punishment on account of the broken oath, in the case of עכן the Israelites lose the battle at עי, in the case of Jonathan, the LORD refuses to answer Saul (I Sam. 14:37).
In both stories, it is known that the oath has been broken, but it is not known WHO broke the oath. In order to discern who it was, the people divide themselves and somehow divine which division is responsible, and then further divide and divine until they discover the culprit. And in both stories, the verb לכד is used to indicate the group or individual who is responsible. Neither story gives details of how this divination actually occurs.
Finally, both stories use the verb עכר, which is a fairly uncommon verb in TaNa”KH.
Is this form of divination common in the Ancient Near East?
The parallel is pointed out by Marsha C. White in Saul in Story and Tradition (p. 132-133). My thanks to Prof. Yitzhak Berger for pointing this out to me (and to Prof. Shalom Holtz for putting me in touch with Prof. Berger).
Also see Matthew Michael “The Achan/Achor Traditions: The Parody of Saul as ‘Achan’ in 1 Samuel 14:24:-15:35.” Old Testament Essays 26:3 (2013)
For more on עכן and עכר see this post.
In the story of the גבעונים, Joshua 9, we have another story of a treaty being made under false circumstances, but the Israelites cannot abrogate this treaty because they have made an oath in the name of יי אלהי ישראל.
Divining is also used when Samuel chooses Saul to be king in I Samuel 10:20-22:
וַיַּקְרֵ֣ב שְׁמוּאֵ֔ל אֵ֖ת כָּל־שִׁבְטֵ֣י יִשְׂרָאֵ֑ל וַיִּלָּכֵ֖ד שֵׁ֥בֶט בִּנְיָמִֽן: וַיַּקְרֵ֞ב אֶת־שֵׁ֤בֶט בִּנְיָמִן֙ למשפחתו לְמִשְׁפְּחֹתָ֔יו וַתִּלָּכֵ֖ד מִשְׁפַּ֣חַת הַמַּטְרִ֑י וַיִּלָּכֵד֙ שָׁא֣וּל בֶּן־קִ֔ישׁ וַיְבַקְשֻׁהוּ וְלֹ֥א נִמְצָֽא: וַיִּשְׁאֲלוּ־עוֹד֙ בַּֽיקֹוָ֔ק הֲבָ֥א ע֖וֹד הֲלֹ֣ם אִ֑ישׁ ס וַיֹּ֣אמֶר יְקֹוָ֔ק הִנֵּה־ה֥וּא נֶחְבָּ֖א אֶל־הַכֵּלִֽים: