╙㧞┨ ᦨૐ⾓㊄ߦ㑐ߔࠆ⚻ᷣℂ⺰ߣታ⸽ಽᨆ㧝 ᦨૐ⾓㊄ߦ㑐ߔࠆ⚻ᷣℂ⺰ ᭎ⷐ
Fuchs et al. (1998) ߪ‫ޔ‬ฦ⒳ഭ௛᡽╷߇Ꮢ႐ߦ෸߷ߔᓇ㗀ߦߟ޿ߡ‫⚻ޔ‬ᷣቇ⠪ߩ੍ᗐߒߚ
୯ࠍ㓸⸘ߒߚ⺰ᢥߢ޽ࠆ‫⺰ޕ‬ᢥߦߪ‫ᦨޟޔ‬ૐ⾓㊄߇ 10㧑਄᣹ߒߚ႐ว‫ޔ‬10 ઍߩ㓹↪㊂ߪߤࠇ߶ߤߩᓇ㗀ࠍฃߌࠆ߆‫߁޿ߣޠ‬໧߇޽ࠆ‫ߦࠇߘޕ‬ኻߔࠆ⚻ᷣቇ⠪ߩ࿁╵ߪ‫ޔ‬ਛᄩ୯ߢ⚂ 1㧑ߩ㓹↪㊂ߩᷫዋߦߟߥ߇ࠆߣ޿߁߽ߩߢ޽ߞߚ‫ޕ‬ഭ௛ࠦࠬ࠻ߩ਄᣹ߦኻᔕߒߡ‫ޔ‬ડᬺߪ㓹↪
㊂ߩ⺞ᢛࠍⴕ߁ߣ‫ޔ‬ᄙߊߩ⚻ᷣቇ⠪ߪ⠨߃ߡ޿ࠆߎߣߦߥࠆ‫ޕ‬ഭ௛Ꮢ႐ߢቢో┹੎߇ᚑ┙ߒ‫ޔ‬߆ߟᦨૐ⾓㊄߇ߘߩቢో┹੎Ꮢ႐ߢߩဋⴧ⾓㊄ࠃࠅ㜞ߊ⸳ቯߐࠇߡ޿ࠆ႐วߪ‫ߥ߁ࠃߩߎޔ‬㓹↪㊂߇ᷫዋߔࠆߣ޿߁ࡠࠫ࠶ࠢߦᓥ߁ߎߣߦߥࠆ‫ޕ‬੐ታ‫ᦨޔ‬ૐ⾓㊄㗵ㄭㄝߩ⡯ߪ㜞޿ᛛ⢻ࠍⷐߒߥ޿߽ߩ߇ᄙߊ‫⧯ߚ߹ޔ‬ᐕጀߩഭ௛⠪߇ᄙߊዞᬺߒߡ޿ࠆ‫ޔ߼ߚߩߘޕ‬ഭ௛ജߩઍᦧ
߇޿ߊࠄߢ߽߈ߊ‫ޔ‬ቢో┹੎ߩ਎⇇ࠍᗐቯߒߡ⦟޿ࠃ߁ߦ߽ᕁ߃ࠆ‫ޕ‬ߒ߆ߒߥ߇ࠄ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߡ߽‫ޔ‬ዋߥߊߣ߽⍴ᦼ⊛ߦߪ㓹↪㊂߇ᷫዋߒߥ޿ߣߒߚ
ታ⸽⎇ⓥ߇‫ޔ‬1990 ᐕઍߦ౉ߞߡ޿ߊߟ߆⊒⴫ߐࠇߚ‫ߩࠄࠇߎޕ‬ታ⸽⚿ᨐߪ‫ᦨޔ‬ૐ⾓㊄߇ᓇ㗀ࠍᜬߟᏒ႐ߦኻߒߡᄙߊߩ⚻ᷣቇ⠪߇᦭ߒߡ޿ߚ‫ޔ‬ቢో┹੎⊛ߥᏒ႐ⷰࠍⷒߔ߽ߩߢ޽ࠆ‫ޕ‬ߘࠇࠁ߃‫ޔ‬ቇ໧਄ߐࠄߦߪ᡽╷਄ߩⷰὐ߆ࠄ߽‫ߩ⽶ޔ‬ᓇ㗀ࠍਈ߃ߥ޿ߣߔࠆ⚿ᨐߪᒝ޿㑐ᔃࠍ㓸߼ࠆߎߣߦߥߞߚ‫ޕ‬ᒰὼ‫ޔ‬㓹↪߇ᷫࠄߥ޿ߣ޿߁⃻⽎ߪ‫ޔ‬න⚐ߥቢో┹੎ࡕ࠺࡞ߩᨒ⚵ߺߢߪ⺑᣿ߢ߈ߥ޿‫ޕ‬㓹↪㊂ߪᷫዋߒߥ޿ߣ⚿⺰ઃߌߚቇ⠪ߚߜ߇‫ޔ‬ઍᦧ᩺ߣߒߡឭ␜ߒߡ
޿ࠆߩߪ‫ޔ‬ഭ௛ߩ㔛ⷐ⁛භࡕ࠺࡞ߢ޽ࠆ‫ޕ‬㔛ⷐ⁛භࡕ࠺࡞ߢߪ‫৻ࠆ޽ޔ‬ቯ᳓Ḱ߹ߢߩᦨૐ⾓㊄਄᣹ߦኻߒߡ‫ޔ‬ડᬺߩ㓹↪㊂߇Ⴧടߔࠆ‫ߩߘޔߚ߹ޕ‬਄᣹ߒߚ⾌↪ߪડᬺ߇⽶ᜂߔࠆߎߣ
ߦߥࠆ‫ߩߎޔߒ߆ߒޕ‬㔛ⷐ⁛භࡕ࠺࡞ߪ‫ޔ‬ቢో┹੎ࡕ࠺࡞߶ߤࠪࡦࡊ࡞ߢߪߥ޿ߚ߼‫ߴߔޔ‬ߡߩቇ⠪߆ࠄหᗧࠍᓧߡ޿ࠆࠊߌߢߪߥ޿‫ᦨޕ‬ૐ⾓㊄߇ᓇ㗀ࠍ෸߷ߔᏒ႐ߪଐὼߣߒߡቢో
┹੎߇ᚑࠅ┙ߟ਎⇇ߥߩ߆‫߽ߣࠇߘޔ‬ቢో┹੎ࡕ࠺࡞ࠍᝥߡߡ೎ߩࡠࠫ࠶ࠢࠍតߐߥ޿ߣ޿
ߌߥ޿ߩ߆‫ޕ‬ឭ಴ߐࠇߡ޿ࠆ⺰ᢥࠍ⷗ࠆ㒢ࠅ‫ޔ‬1990 ᐕઍߦ߅ߌࠆᦨૐ⾓㊄ߩ⺰ὐߪ‫ߦߎߘޔ‬޽ߞߚߣ޿ߞߡ߽ㆊ⸒ߢߪߥ޿‫ޕ‬ߐߡᧄ▵ߢߪ‫ߩߎޔ‬ቢో┹੎ࡕ࠺࡞ߣ‫ޔ‬ഭ௛ߩ㔛ⷐ⁛භࡕ࠺࡞ࠍਛᔃߦ⺑᣿ߔࠆ‫ޔߦઁޕ‬ቢో┹੎ࡕ࠺࡞ߩ᜛ᒛߢ޽ࠆੑㇱ㐷ࡕ࠺࡞߇޽ࠆ‫ޕ‬਄⸥ߢߪ⠨ᘦߐࠇߡ޿ߥ޿ഭ௛⠪ߩ⇣⾰ᕈࠍ⚵ߺㄟࠎߛࡕ࠺࡞╬߽૬ߖߡ‫◲ޔ‬නߦ⚫੺ߔࠆ‫ޕ‬ ቢో┹੎ቢో┹੎⊛ߥഭ௛Ꮢ႐ߢߪ‫ޔ‬Ꮢ႐ߦෳടߒߡ޿ࠆഭ௛⠪ߣડᬺ߇ߘࠇߙࠇห⾰ߢ޽ࠆߣ઒
ቯߐࠇࠆ‫ߩߘޔߚ߹ޕ‬ᢙ߽ᄙᢙߢ޽ࠆߣ઒ቯߐࠇ‫৻ޔ‬ડᬺ߇Ꮢ႐⾓㊄ࠍᠲ૞ߔࠆߎߣߪߢ߈
ߥ޿‫ޔ੹ޕ‬ቢోᏒ႐ࠍ೨ឭߣߒߡ‫ޔ‬ડᬺ߇ഭ௛ߣ⾗ᧄߩ 2 ⽷ࠍ૶ߞߡ↢↥ࠍⴕߞߡ޿ࠆ߽ߩ
ߣߒࠃ߁‫ߩߘޕ‬႐ว‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߪ‫ޔ‬ᰴߩੑߟߩ࡞࡯࠻ࠍㅢߒߡ㓹↪㊂ߦᓇ㗀ࠍਈ߃ࠆ‫ޕ‬㧙㧙৻ߟ⋡ߩ࡞࡯࠻ߪ‫ޔ‬ഭ௛ߣ⾗ᧄߩઍᦧലᨐ‫ޕ‬ੑߟ⋡ߪ‫↥↢ޔ‬㊂ߩᷫዋߦ઻߁㓹↪㊂ߩᷫዋߢ޽ࠅ‫ⷙޔ‬ᮨߩലᨐߣ๭߫ࠇࠆ߽ߩߢ޽ࠆ‫ޕ‬ഭ௛ߣ⾗ᧄߩઍᦧߣߪ‫߇↪⾌ޔ‬㜞ߊߥߞߚഭ௛ࠍ‫⋧ޔ‬ኻ⊛ߦ⾌↪߇቟ߊߥߞߚ⾗ᧄߢ⟎߈឵߃ࠆߣ޿߁߽ߩߢ޽ࠆ‫ߩߣᧄ⾗ޕ‬ઍᦧ߇⿠ߎࠆߎߣߢ‫ߩ޿ࠄߊࠇߤޔ‬㓹↪㊂߇ᷫዋߔࠆ߆
ߪ‫޿ࠄߊࠇߤ߇ᧄ⾗ߩߘޔ‬ഭ௛ߩઍࠊࠅࠍᨐߚߔ߆ߣ޿߁ߎߣߦଐሽߒߡߊࠆ‫ޕ‬ᰴߦ‫↥↢ޔ‬㊂ߩᷫዋߦ઻߁㓹↪ߩᷫዋߩലᨐࠍ⹦ߒߊ⺑᣿ߔࠆߣ‫ޔ‬એਅߩࠃ߁ߥ߽ߩߣߥ
ࠆ‫ᦨޔߕ߹ޕ‬ૐ⾓㊄߇਄᣹ߔࠆߣഭ௛ࠦࠬ࠻߇㜞ߊߥࠆߩߢ‫ޔ‬ડᬺߪ਄᣹ಽߩ৻ㇱࠍ↢↥‛ߩଔᩰߦォᇾߒࠃ߁ߣߔࠆ‫⾓ޔߜࠊߥߔޕ‬㊄ߩ਄᣹ߦ઻߁ࠦࠬ࠻࡮ࡊ࠶ࠪࡘ࡮ࠗࡦࡈ࡟࡯ࠪ
࡚ࡦߩ⊒↢ߢ޽ࠆ‫ߢߎߎޔߒ߆ߒޕ‬ડᬺ߇↢↥‛ߩଔᩰࠍ਄᣹ߐߖࠆߣ‫ޔ‬೑Ảࠍᦨᄢߦߔࠆ
ᦨㆡ↢↥㊂ߪᷫዋߔࠆߎߣߦߥࠆ‫⽷ޔߪ‛↥↢ޔࠄߥߗߥޕ‬Ꮢ႐ߢ㔛ⷐߩ೙⚂ࠍฃߌߡ޿ࠆ
߆ࠄߢ޽ࠆ‫ޕ‬㔛ⷐߩ೙⚂ߣߪ‫ޔ‬ଔᩰ߇਄߇ࠆߣᶖ⾌⠪ߩ㔛ⷐ㊂߇ᷫࠆߎߣࠍᗧ๧ߔࠆ‫ᦨޕ‬ㆡߥ↢↥㊂߇ᷫዋߔࠆߣ‫↥↢ߩߘޔ‬㊂ࠍታ⃻ߔࠆߚ߼ߦᔅⷐߥഭ௛ᛩ౉㊂߽ᷫዋߔࠆߎߣߦߥ
ࠆ‫ޕ‬ഭ௛㓸⚂⊛ߥ↢↥ࠍⴕߞߡ޿ࠆડᬺ߶ߤ‫ߩߘޔ‬ಽഭ௛ࠦࠬ࠻߇㜞ߊߥࠆߚ߼‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߦࠃࠅᄙߊߩ㓹↪㊂ࠍᷫዋߐߖࠆߎߣ߇⠨߃ࠄࠇࠆ‫ޔߚ߹ޕ‬㔛ⷐ㊂߇ଔᩰᄌേߩᓇ㗀ࠍฃߌ߿ߔ޿⽷ࠍ↢↥ߒߡ޿ࠆડᬺ߽‫↥↢ߩߘޔ‬㊂߇ᄢ߈ߊૐਅߔࠆߚ߼ߦ‫ޔ‬㓹↪㊂ࠍᄢ߈ߊᷫࠄߔ‫ޔߦ⊛⥸৻ޕ‬㘶㘩ᬺ߿ዊᄁᬺ‫↥⛽❫ߪ޿ࠆ޽ޔ‬ᬺߥߤߪ‫ߥ߁ࠃߩߎޔ‬௑ะ߇ᒝ޿ߎ
ߣ߇⠨߃ࠄࠇࠆ‫ޕ‬࿑㧞㧙㧝 ቢో┹੎ࡕ࠺࡞ߣᦨ⾓ߩᓇ㗀
W
S

wm
w*

D

E’

E

S

❑ゲߦ⾓㊄‫ޔ‬ᮮゲߦ㓹↪㊂㧔ഭ௛ജ㧕ࠍߣࠅ‫ޔ‬ഭ௛㔛ⷐᦛ✢ߣഭ௛ଏ⛎ᦛ✢ࠍࡊࡠ࠶࠻ߒ
ߚ߽ߩ߇‫ޔ‬࿑ 2㧙1 ߢ޽ࠆ‫ᦨޕ‬ૐ⾓㊄߇ሽ࿷ߒߥ޿႐ว‫ޔ‬ഭ௛㔛ⷐ㊂ߣഭ௛ଏ⛎㊂߇৻⥌ߔࠆਔᦛ✢ߩ੤ὐ߇‫ߩߎޔ‬Ꮢ႐ߩဋⴧὐߣߒߡ⴫ߐࠇࠆ‫⾓ߩ߈ߣߩߘޕ‬㊄᳓Ḱ w*߇ဋⴧ⾓㊄㧙㧙ߢ޽ࠅ‫ޔ‬E ὐ߇ဋⴧ㓹↪㊂ߣߥࠆ‫ޕ‬ߐߡ‫ᦨޔ‬ૐ⾓㊄߇ဋⴧ⾓㊄ࠃࠅ㜞޿‫ޔ‬wm ߦ⸳ቯߐࠇࠆߣߔࠆ‫ߩߎޕ‬႐ว‫ޔ‬ഭ௛㔛ⷐߪ㧱’ὐ߹ߢᷫዋߔࠆ‫ߩߎޕ‬ᷫዋߪ‫ޔ‬਄⸥ߩઍᦧߣ↢↥㊂❗ዊ‫ޔ‬ੑߟߩലᨐࠍ⿷ߒวࠊߖߚ߽ߩߢ
޽ࠆ‫ޕ‬ㅒߦ‫ޔ‬ഭ௛ଏ⛎ߪឭ␜ߐࠇࠆ⾓㊄߇਄߇ࠆߚ߼ߦ‫ޔ‬S ὐ߹ߢჇടߔࠆߎߣ߇੍ᗐߐࠇ
ࠆ‫ޕ‬㔛ⷐ஥ߩⷐ࿃ߦࠃߞߡ㓹↪㊂߇᳿ቯߐࠇࠆߣߔࠇ߫‫ޔ‬Ꮢ႐ߢߪ S㧙E’ಽߛߌഭ௛ߩ⿥ㆊ
ଏ⛎߇↢ߓ‫ߩߘޔ‬㊂߇ᄬᬺ⠪ᢙߣߒߡ⸘਄ߐࠇࠆߎߣߦߥࠆ‫ߚ߹ޕ‬㓹↪㊂ߩᄌൻߛߌࠍ⷗ߡ
߽‫ᦨޔ‬ૐ⾓㊄߇ሽ࿷ߒߥ޿႐วߦᲧߴߡ‫ޔ‬E㧙E’ߛߌᷫዋߒߡ޿ࠆ‫ޕ‬㓹↪⠪ᢙߩᷫዋ‫ࠆ޽ޔ‬޿ߪᄬᬺ⠪ᢙߩჇടߪ‫⸳ޔ‬ቯߐࠇߚᦨૐ⾓㊄ߩ㗵ߣဋⴧ⾓㊄ߣߩਵ㔌᏷ߦଐሽߒߡ޿ࠆߎߣ
߇‫ޔ‬࿑ 2㧙1 ࠃࠅ⷗ߡขࠇࠆ‫ޔߚ߹ޕ‬㓹↪⠪ᢙߩᷫዋߣᄬᬺ⠪ᢙߩჇടߪ‫ࠇߙࠇߘޔ‬ഭ௛㔛ⷐߣഭ௛ଏ⛎ߩ⾓㊄ߦ㑐ߔࠆᒢജᕈߦ߽ଐሽߒߡ޿ࠆ‫ޕ‬㓹↪ߩ⾓㊄ᒢജᕈߣߪ⾓㊄߇㧝㧑ᄌൻߒߚߣ߈ߦ‫ޔ‬㓹↪߇૗㧑ᄌൻߔࠆ߆ࠍ␜ߒߚ୯ߢ޽ࠆ‫ޔ߫߃଀ޕ‬࿑ 2㧙1 ߦ߅ߌࠆ㔛ⷐᦛ✢ߣଏ⛎ᦛ✢߇‫ߩߎޕ߁ࠃߒߣߩ߽ࠆࠇߐ⴫ߢ✢⋥ࠇߙࠇߘޔ‬႐ว‫ޔ‬ဋⴧὐ W ߦ߅ߌࠆᒢജ
ᕈߪ‫ޔ‬ਔᦛ✢ߩ௑߈ߩㅒᢙߦဋⴧὐߢߩ⾓㊄ߣ㓹↪ߩᲧ₸㧔W*㧛E㧕ࠍ߆ߌߚ߽ߩߣߥࠆ‫ޕ‬ࠃߞߡ‫ޔ‬࿑ 2㧙1 ߢߪ⋥✢ߩ௑߈߇᳓ᐔߢ޽ࠇ߫޽ࠆ߶ߤ‫ޔ‬ᒢജᕈߩ୯ߪᄢ߈ߊߥࠅ‫⾓ޔ‬㊄
ߩᄌൻߦኻߒߡ㓹↪߇ᄢ߈ߊ෻ᔕߔࠆߎߣߦߥࠆ‫ޕ‬ ੑㇱ㐷ࡕ࠺࡞☨࿖ߩᦨૐ⾓㊄೙ᐲߪ‫౏ޔ‬ᱜഭ௛ၮḰᴺߦࠃࠅⷙቯߐࠇߡ޿ࠆ‫ ߒ߆ߒޕ‬1938 ᐕߩ೙ቯએ
᧪‫౏ޔ‬ᱜഭ௛ၮḰᴺߪ‫ోޔ‬㓹↪ਥߦኻߒߡߘߩ㓹↪⠪ߦᦨૐ⾓㊄㗵એ਄ߩ⾓㊄ࠍᛄ߁ߎߣࠍ
⟵ോઃߌߡ޿ߚࠊߌߢߪߥ޿‫ޔߪߦߎߘޕ‬ㆡ↪ߩኻ⽎߆ࠄᄖࠇࠆ↥ᬺ߿⡯⒳߇ሽ࿷ߒߡ޿ߚ‫ޕ‬ߎߩ੐ታࠍ〯߹߃‫ޔ‬ቢో┹੎ࡕ࠺࡞ߦᦝߦ⃻ታ๧ࠍᜬߚߖࠆߚ߼‫ᦨޔ‬ૐ⾓㊄߇ㆡ↪ߐࠇߚㇱ㐷ߣㆡ↪ߐࠇߡ޿ߥ޿ㇱ㐷ߩੑߟߦᏒ႐ࠍಽᢿߒߚ‫ޔ‬ੑㇱ㐷ࡕ࠺࡞߇ Welch (1976) ߦࠃߞߡዷ㐿ߐࠇߡ޿ࠆ‫ޕ‬
Welch (1976) ߩੑㇱ㐷ࡕ࠺࡞ࠍ࿑␜ߒߚߩ߇‫ޔ‬࿑ 2㧙2 ߢ޽ࠆ‫ᦨޕ‬ૐ⾓㊄߇⸳ቯߐࠇࠆ೨
ߪ‫ޔ‬ਔㇱ㐷ߢหߓ⾓㊄㗵 Wo ߢဋⴧ߇ᚑ┙ߒߡ޿ࠆ߽ߩߣߔࠆ‫ᦨߢߎߎޕ‬ૐ⾓㊄ Wm ߇⸳ቯߐࠇࠆߣ‫߇⾓ᦨޔ‬ㆡ↪ߐࠇࠆㇱ㐷ߢ⿥ㆊଏ⛎߇↢ߓࠆ‫ߡߞࠃޕ‬ㆡ↪ㇱ㐷ߢߩ㓹↪㊂ߪ‫ޔ‬E0C
߆ࠄ EmC ߳ߣᷫዋߔࠆ‫ޕ‬ㆡ↪ㇱ㐷ߢ⡯ࠍᄬߞߚഭ௛⠪ߩ৻ㇱߪ‫ޔ‬ዞᬺᯏળ߇଻⸽ߐࠇߚ㕖ㆡ↪ㇱ㐷߳ߣ⒖േߔࠆน⢻ᕈ߇޽ࠆ‫ߩߎޕ‬േ߈ߪ㕖ㆡ↪ㇱ㐷ߦ߅ߌࠆ‫ޔ‬ഭ௛ଏ⛎ᦛ✢ߩࠪࡈ࠻ߣߒߡ␜ߐࠇࠆ㧔Su ψ Su’㧕‫ޕ‬㕖ㆡ↪ㇱ㐷ߢߩഭ௛ଏ⛎ߩჇടߪ‫⚿ޔ‬ᨐߣߒߡ㕖ㆡ↪ㇱ㐷ߢ
ߩဋⴧ⾓㊄ࠍ Wu ߹ߢ᛼ߒਅߍࠆߎߣߦߥࠆ‫ᦨޔߦ߃ࠁޕ‬ૐ⾓㊄߇ㆡ↪ߐࠇߡ޿ࠆㇱ㐷ߣㆡ↪ࠍฃߌߡ޿ߥ޿ㇱ㐷ߩ㑆ߢߩ⾓㊄ᩰᏅߪ‫⸳ޔ‬ቯߐࠇߚᦨૐ⾓㊄ߣᒰೋߩဋⴧ⾓㊄ Wo ߣߩᏅએ਄ߩᩰᏅߦߥࠆ‫⾓ޔߒ߆ߒޕ‬㊄ߦࠃࠆ೙⚂߇ߥ޿ߚ߼‫ޔ‬㕖ㆡ↪ㇱ㐷ߢߩ㓹↪㊂ߪჇടߔࠆߎߣߦߥࠆ‫ߩ⾓ᦨޔࠅ߹ߟޕ‬ㆡ↪㒰ᄖᨒࠍ⸳ߌࠆߎߣߢ‫⾓ޔ‬㊄ߩᩰᏅߪ㐿ߊߎߣߦߥࠆ߇‫ޔ‬㒰ᄖᨒࠍ⸳ߌߥ޿႐วߦᲧߴߡᏒ႐ో૕ߩ㓹↪㊂ᷫዋߪዋߥߊߡߔ߻‫࡞࠺ࡕߩߎޔ߇ࠇߘޕ‬ߩࠗࡦࡊ࡝ࠤ࡯࡚ࠪࡦߢ޽ࠆ‫ޕ‬㧙㧙࿑㧞㧙㧞 ੑㇱ㐷ࡕ࠺࡞
Su

Sc

Su’

Wm

Wo

Wo

Wu
Dc
Emc

Du

EoC

Eou

ㆡ↪ㇱ㐷

E1u

㕖ㆡ↪ㇱ㐷

߹ߚ‫ޔ‬Mincer (1976) ߣ Gramlish (1976) ߪߎߩੑㇱ㐷ࡕ࠺࡞ߦ‫ޔ‬ᄬᬺࠍ⚵ߺㄟࠎߛ᜛ᒛ
ࠍⴕߞߡ޿ࠆ‫ޔߪߢ࡞࠺ࡕޕ‬㕖ㆡ↪ㇱ㐷ߦⴕߌ߫ߔߋߦ⡯߇⷗ߟ߆ࠆߦ߽㑐ࠊࠄߕ‫ޔ‬ഭ௛⠪ߩ৻ㇱߪ⾓㊄ߩ㜞޿ㆡ↪ㇱ㐷ߦߣߤ߹ࠅߘߎߢ⡯ߦዞߌࠆ߹ߢᓙߟ‫ޔࠅ߹ߟޕ‬ㆡ↪ㇱ㐷ߦ߅ߌࠆᄬᬺߩ⊒↢ࠍ⹺߼ߡ޿ࠆ‫ޕ‬ᄬᬺࠍ⠨ᘦߒߚ Mincer ߣ Gramlish ߩࡕ࠺࡞ߪ‫ޔ‬Welch ߩࡕ࠺࡞ߣߪ⇣ߥࠅ‫ޔ‬ㆡ↪ㇱ㐷ߩ⾓㊄਄᣹߇‫ޔ‬ᔅߕߒ߽㕖ㆡ↪ㇱ㐷ߢߩ⾓㊄ਅ⪭ߦߪߟߥ߇ࠄ
ߥ޿‫ޕ‬ㆡ↪ㇱ㐷ߢߩഭ௛㔛ⷐ߇ᒢജ⊛ߢߥ޿႐ว‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߪ㕖ㆡ↪ㇱ㐷ߩ⾓㊄߽਄᣹ߐߖ‫ޔ‬ઍࠅߦᄬᬺ₸߇਄᣹ߔࠆߎߣߦߥࠆ‫ޕ‬ ഭ௛ߩ㔛ⷐ⁛භቢో┹੎ࡕ࠺࡞ࠍ೨ឭߦ⼏⺰ࠍㅴ߼ߚ႐ว‫ޔ‬ဋⴧ⾓㊄એ਄ߩ᳓Ḱߦᦨૐ⾓㊄߇⸳ቯߐࠇࠆ
ߣ‫ޔ‬㓹↪㊂߇ᷫዋߔࠆߎߣ߇␜ߐࠇߚ‫ޔߒ߆ߒޕ‬ડᬺߦഭ௛ߩ㔛ⷐ⁛භജ߇޽ࠆࠃ߁ߦ઒ቯ
ߔࠇ߫‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߦࠃߞߡ‫ޔ‬ᔅߕߒ߽㓹↪㊂ߪᷫዋߒߥ޿ߎߣ߇␜ߐࠇࠆ‫ޕ‬ഭ௛ߩ㔛ⷐ⁛භߣߪ‫ޔ‬ഭ௛Ꮢ႐ߦߪ৻ߟߩડᬺߒ߆ෳടߒߡ߅ࠄߕ‫ߩ␠ઁ߃ࠁࠇߘޔ‬േ߈ࠍ᳇ߦߔࠆ
ߎߣߥߊ‫ޔ‬ഭ௛ࠍ೑↪ߔࠆߎߣ߇ߢ߈ࠆߣ޿߁߽ߩߢ޽ࠆ‫ޕ‬ડᬺၔਅ↸ߪ‫ߥ߁ࠃߩߘޔ‬Ꮢ႐ߩઍ⴫଀ߢ޽ࠆ‫ޔߚ߹ޕ‬ഭ௛⠪ࠍᒁ߈ઃߌࠆ߶ߤߩࡉ࡜ࡦ࠼ജࠍᜬߟડᬺ߽‫ࠆ޽ޔ‬⒟ᐲߩ㔛ⷐ⁛භജࠍ᦭ߒߡ޿ࠆߣ⠨߃ࠄࠇࠆ‫ޕ‬ഭ௛ߩ㔛ⷐ⁛භࡕ࠺࡞ߣቢో┹੎ࡕ࠺࡞ߣߩᄢ߈ߥ㆑
޿ߪ‫ޔ‬ഭ௛⠪ߩ⾓㊄ࠍડᬺ߇ࠦࡦ࠻ࡠ࡯࡞ߢ߈ࠆ߆ߤ߁߆ߣ޿߁ߎߣߢ޽ࠆ‫ޕ‬ቢో┹੎ࡕ࠺࡞ߢߪ‫ޔ‬ડᬺ߇⾓㊄ࠍࠦࡦ࠻ࡠ࡯࡞ߔࠆജࠍᜬߚߥ޿ߚ߼‫ޔ‬ห⾰ߥഭ௛⠪ߩ⾓㊄ߪᏒ႐ߩࡔ
ࠞ࠾࠭ࡓߦࠃࠅ৻ᓞߦቯ߹ࠆ‫ઁޕ‬ᣇ‫ޔ‬ડᬺ߇ഭ௛ࠍ⁛භߢ߈ࠆ႐ว‫ޔ‬ડᬺߪ⾓㊄ࠍㅢߓߡഭ
௛㊂ࠍჇᷫߔࠆߎߣ߇น⢻ߣߥࠆ‫ߩߘޕ‬㓙‫⾓ޔ‬㊄ߣ㓹↪㊂ߩ㑐ଥߪ‫⾓ߩࠄߊ޿ޔ‬㊄ߢ޽ࠇ߫௛ߊ߆ߣ޿߁‫ޔ‬ഭ௛⠪ߩଏ⛎ⴕേߦࠃߞߡ೙⚂ࠍฃߌࠆߎߣߦߥࠆ‫ޕ‬㧙㧙߹ߕ‫ᦨޔ‬ૐ⾓㊄߇⑼ߖࠄࠇࠆ೨ߦ‫⁛ޔ‬භડᬺ߇ߤߩࠃ߁ߦᦨㆡߥ㓹↪㊂ࠍ᳿ቯߔࠆ߆⷗ߡ
߅ߎ߁‫ޕ‬ડᬺߪ‫ޔ‬ฝ਄߇ࠅߩഭ௛ଏ⛎ᦛ✢ߦ⋥㕙ߒߡ޿ࠆߣߔࠆ‫߈ߣߩߎޕ‬ડᬺߪ‫ޔ‬ഭ௛ଏ⛎ᦛ✢ߩㅒ㑐ᢙ‫ޔ‬w = w (L) ࠍ೨ឭߣߒߡ‫ޔ‬೑Ảࠍᦨᄢൻߔࠆࠃ߁ߦദ߼ࠆ‫ޕ‬ડᬺߩ೑Ả㑐ᢙࠍ
Ǹ = R (L) – w (L) L(1),ߣቯ⟵ߔࠆ‫ޔߢߎߎޕ‬L ࠍഭ௛⠪ᢙߣߔࠆ‫ޕ‬R(L)ࠍડᬺߩ෼౉㑐ᢙߣߒ‫ޔ‬w(L)L ߪ⾓㊄ߦഭ௛⠪ᢙࠍ߆ߌߚ߽ߩ‫ੱࠅ߹ߟޔ‬ઙ⾌ߢ޽ࠆ‫ޕ‬L ࠍേ߆ߔߎߣߦࠃߞߡ‫ޔ‬೑ẢǸࠍᦨᄢൻߔࠆߦߪ
R’ (L) – w (L) – w’ (L) L = 0

(2).

ߔߥࠊߜ
R’ (L) = w (L) + w’ (L) L(3),ࠍḩߚߔ L ߇ㆬᛯߐࠇࠆᔅⷐ߇޽ࠆ‫(ޕ‬2)㧘(3)ᑼߩ R’(L)ߪ‫ޔ‬ഭ௛ജࠍ㧝න૏Ⴧ߿ߒߚߣ߈ߩડ ᬺ ෼ ౉ ߩ Ⴧ ട ಽ ࠍ ␜ ߒ ߡ ߅ ࠅ ‫ ޔ‬ഭ ௛ ߩ 㒢 ⇇ ෼ ౉ ↢ ↥ ‛ 㧔 MRP㧕 ߣ ๭ ߫ ࠇ ࠆ ‫ ઁ ޕ‬ᣇ ‫ޔ‬
w(L)+w’(L)L ߪ‫ޔ‬ഭ௛ജࠍ৻න૏Ⴧടߐߖߚߣ߈ߦ߆߆ࠆㅊട⊛⾌↪‫ߜࠊߥߔޔ‬ഭ௛ߩ㒢⇇⾌↪㧔MCL㧕ߣ๭߫ࠇࠆ߽ߩߢ޽ࠆ‫ޕ‬ഭ௛ଏ⛎ᦛ✢ߩㅒ㑐ᢙ߽ฝ޽߇ࠅߢ޽ࠆߚ߼‫ޔ‬᭎ᔨ⊛ߦߪ‫ޔ‬ഭ௛㊂ࠍჇ߿ߔߣ㓹↪⠪৻ੱ޽ߚࠅߩ⾓㊄߇਄᣹ߔࠆߎߣߦߥࠆ‫ޔߡߞࠃޕ‬ഭ௛ജࠍ
1 න૏Ⴧ߿ߔߦߪ‫ߩߢ߹੹ޔ‬㓹↪ߒߡ޿ࠆ⠪ోຬߩ⾓਄ߍࠍߒߥߌࠇ߫ߥࠄߥ޿‫ޕ‬㒢⇇⾌↪
ߪ⾓㊄ࡊ࡜ࠬ w’(L)L ಽߛߌᔅⷐߣߥࠆ‫(ޕ‬3)ᑼࠃࠅ೑Ảᦨᄢൻὐߢߪ‫ޔ‬ഭ௛ߩ㒢⇇෼౉↢↥‛߇ഭ௛ߩ㒢⇇⾌↪ߣ৻⥌ߔࠆ‫ޕ‬࿑㧞㧙㧟 ⾈޿ᚻ⁛භਅߦ߅ߌࠆᦨૐ⾓㊄ߩᓇ㗀
W
MCL

w’’

C
w(L)
B

w’
w*

A
MRP

L

L’

㧙㧙

਄⸥ߩ⁛භડᬺߩⴕേࠍ࿑␜ߔࠆߣ࿑ 2㧙3 ߩࠃ߁ߦߥࠆ‫ޕ‬࿑ 2㧙3 ߩᦛ✢ MRP ߪ‫ޔ‬ഭ௛ᛩ౉㊂ߣ‫ߩߘޔ‬ഭ௛ᛩ౉㊂ߩ߽ߣߢታ⃻ߐࠇࠆ㒢⇇෼౉↢↥‛ߩฬ⋡⃻㊄ଔ୯ࠍࡊࡠ࠶࠻ߒ
ߚ߽ߩߢ޽ࠆ‫ઁޕ‬ᣇ‫ޔ‬MCL ߪഭ௛ᛩ౉㊂ߣߘߩ㒢⇇⾌↪ࠍࡊࡠ࠶࠻ߒߚ߽ߩߦߥࠆ‫(ޕ‬3)ᑼ
ߢ⷗ߚࠃ߁ߦ‫ޔ‬ഭ௛ߩ㔛ⷐ⁛භߩਅߢ‫ᦨޔ‬ㆡ㓹↪㊂ L ߪ MRP ߣ MCL ߇৻⥌ߔࠆὐߢ᳿߹
ߞߚ‫ߩߎޔߚ߹ޕ‬㓹↪㊂ L ࠍታ⃻ߔࠆߚ߼ߦߪ‫ޔ‬ഭ௛ଏ⛎ᦛ✢ߩㅒ㑐ᢙ w = w(L)߆ࠄ‫ޔ‬ડᬺ
ߪ⾓㊄ w*ࠍឭ␜ߔࠆߛߌߢࠃ޿‫⾓ߩߎޕ‬㊄ߣ㓹↪㊂ߩ⚵วߖߪ‫ޔ‬࿑ 2㧙3 ߩ A ὐߢ␜ߐࠇࠆ‫ޕ‬ὐ A ߦ߅޿ߡડᬺߪᱜߩ೑Ảࠍᓧߡ߅ࠅ‫ߟ߆ޔ‬ᓧࠄࠇࠆ೑Ả߇ᦨᄢߣߥࠆὐߢ޽ࠆ‫ߺߥߜޕ‬ߦቢో┹੎ߩ਎⇇ߢߪ‫ߩߎޔ‬ડᬺ೑Ả߇࠯ࡠߣߥࠆ‫ޕ‬ߢߪ‫⁛ޔ‬භߩ߽ߣߢᦨૐ⾓㊄߇਄᣹ߒߚ႐ว‫ޔ‬㓹↪ߪߤߩࠃ߁ߦᄌൻߔࠆߢ޽ࠈ߁߆‫ᦨޕ‬
ૐ⾓㊄߇ w*એਅߦ⸳ቯߐࠇࠆ႐ว‫ޔ‬ડᬺߪᦨૐ⾓㊄ߩ㗵એ਄ߩ w*ࠍឭ␜ߒߡ L ߛߌߩ㓹↪
㊂ࠍታ⃻ߔࠆ‫ᦨޔߦ߃ࠁޕ‬ૐ⾓㊄ߩ⸳ቯߪ㓹↪㊂‫⾓ޔ‬㊄౒ߦᓇ㗀ࠍ෸߷ߐߥ޿‫ᦨޕ‬ૐ⾓㊄߇
ὐ A ߣᦛ✢ MRP ߩ੤ὐߢߩ⾓㊄ w’ߩ㑆ߦ⸳ቯߐࠇࠆߣ‫ޔ‬ᒰೋߩ㓹↪᳓Ḱ L ࠃࠅ㓹↪㊂ߪჇ
ടߔࠆ‫▸ߩߎޕ‬࿐ߢߪ‫ߛ߹ޔ‬ഭ௛ߩ㒢⇇↢↥‛⾓෼౉ߩᣇ߇⾓㊄ࠃࠅ߽㜞޿‫⸳ࠅ߹ߟޕ‬ቯߐࠇߚᦨૐ⾓㊄ߩ᳓Ḱߣ‫(ࠍࠇߘޔ‬3)ߦઍ౉ߒߡᓧࠄࠇࠆഭ௛ജߩ⚵วߖߢડᬺߪᠲᬺࠍⴕ߁‫ޕ‬ᓧࠄࠇࠆ೑Ả⥄૕ߪ‫ޔ‬A ߩ⚵วߖࠃࠅ߽ਅ߇ࠆ‫ᦨࠅ߹ߟޔ‬ૐ⾓㊄਄᣹ߩࠦࠬ࠻ࠍડᬺ߇⽶ᜂߒߡ޿ࠆߩߢ޽ࠆ߇‫ޔ‬ડᬺߪߥ߅ᱜߩ೑Ảࠍ੨ฃߔࠆߎߣ߇ߢ߈ࠆ‫ޔߒ߆ߒޕ‬w’એ਄ߦᦨૐ
⾓㊄ߩ㗵߇਄߇ࠆߣ‫ ✢ᦛޔ‬MRP ߦᴪߞߡ㓹↪㊂ߪ L’߆ࠄᷫዋߒᆎ߼ࠆ‫ ✢ᦛޕ‬MRP ਄ߩ㓹
↪㊂ߣ⾓㊄ߩ⚵วߖߪ‫ޔ‬ડᬺߩ㒢⇇೑Ả߇࠯ࡠߣߥࠆ⚵วߖߩ゠〔ߢ޽ࠆ‫✢ᦛޔࠅ߹ߟޕ‬MRP ߩᄖ஥ߢ↢↥ࠍⴕ߁ߣડᬺߩ㒢⇇೑Ảߪ⽶ߣߥࠆ‫ᦨޔߜࠊߥߔޕ‬ૐ⾓㊄߇ w’એ਄ߦ⸳ቯߐࠇߚߣ߈‫ޔ‬ડᬺߪ㓹↪㊂ࠍ೥ᷫߔࠆߎߣߦࠃߞߡ‫ޔ‬ഭ௛ߩ㒢⇇෼౉↢↥‛ߩ୯ࠍ਄ߍࠆ‫ޕ‬ߐߡ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦਈ߃ࠆᓇ㗀ࠍ‫ޔ‬ౣᐲ‫ޔ‬࿑ 2㧙3 ࠍ↪޿ߡᢛℂߒߡߺࠃ߁‫ᦨޕ‬ૐ⾓㊄߇⑼ߖࠄࠇߥ޿႐ว‫ ߪ޿ࠆ޽ޔ‬w*એਅߩ႐วߪ‫ޔ‬A ὐߢ㓹↪ߣ⾓㊄ߩ⚵วߖ߇᳿߹ࠆ‫ᦨޕ‬
ૐ⾓㊄߇ w*߆ࠄ w’ߩ▸࿐ߢߪ‫ޔ‬ㅒଏ⛎ᦛ✢ w(L)਄ߩὐߢ᳿߹ࠆ‫ޕ‬w’એ਄ߩᦨૐ⾓㊄߇⑼ߖ
ࠄࠇߚ႐ว‫ޔ‬ડᬺߪᦛ✢ MRP ਄ߩ㓹↪㊂ࠍㆬᛯߒߡ޿ߊ‫ߡߞࠃޕ‬ㅒଏ⛎ᦛ✢ w(L)ߣᦛ✢MRP ߩ੤ὐ B ߇‫ᦨޔ‬ૐ⾓㊄ࠍ⑼ߔߎߣߦࠃࠅታ⃻ߢ߈ࠆᦨᄢߩ㓹↪㊂ߣߥࠆ‫ߩߎޕ‬ὐ߹ߢ
ߪᦨૐ⾓㊄਄᣹ߩࠦࠬ࠻ߪડᬺ߇⽶ᜂߔࠆߎߣߦߥࠆ‫ᦨޕ‬ૐ⾓㊄߇⑼ߖࠄࠇߥ߆ߞߚ႐วߩ
㓹↪㊂ L ࠍၮḰߦ㓹↪㊂ߩჇᷫࠍ⠨߃ࠆߣ‫ ✢ᦛޔ‬MRP ߣᦛ✢ MCL ߩ੤ὐ C ߢᚑ┙ߔࠆ⾓㊄‫ޔ‬w’’߹ߢߩ▸࿐ߢᦨૐ⾓㊄߇⸳ቯߐࠇߚ႐วߪ‫ޔ‬㓹↪㊂߇Ⴧടߔࠆߎߣߦߥࠆ‫ޕ‬ߢߪ‫ᦨޔ‬ૐ⾓㊄߇⑼ߖࠄࠇߥ޿ߣ߈ߦᓧࠄࠇࠆ㓹↪㊂ L ࠃࠅ‫ޔ‬㓹↪㊂߇ᷫዋߒߥ޿ᦨૐ⾓㊄ߩ਄᣹᏷ࠍᢙ୯ߢ⴫ߖ߫ߤ߁ߥࠆߢ޽ࠈ߁߆‫ޕ‬ഭ௛ߩ㒢⇇⾌↪‫ޔ‬w(L) + w’(L)L ࠍᄌᒻߔࠆߣ w(1+1/ǯ)ߣߥࠆ‫ߢߎߎޕ‬ǯߪഭ௛ଏ⛎ߩᒢജᕈߢ޽ࠆ‫ᦨޕ‬ૐ⾓㊄߇ဋⴧ⾓㊄ߩ 1+1/ǯ୚߹ߢߦ⸳ቯߐࠇࠆߥࠄ߫‫ޔ‬㓹↪㊂ߪᒰೋߩဋⴧ㓹↪㊂ L ࠃࠅჇടߔࠆߎߣߦߥࠆ‫ࠅ߹ߟޕ‬w’ = w*(1+1/ǯ)ߢ޽ࠆ‫ޕ‬ǯ߇࠯ࡠߦㄭ޿୯ࠍߣࠆߣ‫ޔ‬ᒰೋߩဋⴧ㓹↪㊂ L ࠍᷫࠄߔߎߣߥߊ‫ޔ‬㜞޿ᦨૐ⾓㊄ࠍ⸳ቯߔࠆߎߣ߇น⢻ߦߥࠆ‫ޕ‬ㅒߦ‫ޔ‬ǯ߇ή㒢ᄢߦㄭߠߊߣଏ⛎ᦛ✢ߪ᳓ᐔߦߥࠅ‫ޔ‬㓹↪㊂ L ࠍᷫࠄߐߥ޿ᦨૐ⾓㊄ߩ⸳ቯ᏷ߪ⁜߹ࠆߎߣߦߥࠆ‫ޕ‬㧙㧙 േቇࡕ࠺࡞
ㅢᏱ‫ߩߘޔ‬Ꮢ႐ߩഭ௛ജࠍ⁛භߢ߈ࠆࠃ߁ߥડᬺߪ‫࠼ࡦ࡜ࡉޔ‬ജ߿ଔᩰᡰ㈩ജߥߤ‫ޔ‬Ꮢ႐ߦኻߒߡ૗ࠄ߆ߩᒝ޿ᓇ㗀ജࠍ߽ߞߡ޿ࠆ‫ޔࠄ߇ߥߒ߆ߒޕ‬ഭ௛⠪ߦኻߒߡᦨૐ⾓㊄ࠍឭ␜ߔࠆડᬺߪ‫ޔ‬ዊᄁࠅ߿࡟ࠬ࠻࡜ࡦߥߤߩ㔖⚦ડᬺ߇ᄙ޿‫ޔߚ߹ޕ‬หᬺ⠪ᢙ߽ᄙ޿ߚ߼‫ߩߘޔ‬৻ડᬺߦ㓹ࠊࠇߡ޿ࠆᓥᬺຬߩᢙ߇㕖ᾫ✵ഭ௛⠪ో૕ߩᏒ႐ߦභ߼ࠆഀวߪ‫ޔ‬ήⷞߢ߈ࠆ߶
ߤዊߐ޿߽ߩߢ޽ࠆ‫ߡߞࠃޕ‬਄⸥ߩ⾈޿ᚻ⁛භࡕ࠺࡞ߩߺߢ‫ᦨޔ‬ૐ⾓㊄߇ഭ௛Ꮢ႐ߦਈ߃ࠆ
ᓇ㗀ࠍ⺰ߓࠆߎߣߪ㔍ߒ޿‫ޕ‬Card and Krueger (1995) ߪ‫ޔ‬ഭ௛⠪ߩ㔌⡯ߣណ↪‫ࠅ߹ߟޔ‬⡯ߩត⚝ⴕേࠍࡕ࠺࡞ߦ฽߼ࠆߎߣߢ‫ޔ‬Ꮢ႐ߦኻߒߡᓇ㗀ജࠍᜬߚߥ޿ડᬺߢ߽‫⁛ޔ‬භജࠍ᦭ߒߚ⁁ᴫࠍ૞ࠅ಴ߖࠆߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬ቢో┹੎‫ߪ޿ࠆ޽ޔ‬ഭ௛ജߩ⾈޿ᚻ⁛භࡕ࠺࡞ߢߪ‫ޔ‬ቢోᖱႎ߇઒ቯߐࠇߡ޿ࠆ‫ߢߎߎޕ‬ߩቢోᖱႎߣߪ‫ޔ‬ഭ௛⠪߇ൕ߼ࠆ೨ߦ઀੐ߩౝኈࠍචಽߦᛠីߒߡ޿ࠆߣ޿߁ߎߣߢ޽ࠆ‫ޕ‬ࠃߞߡᖱႎ߇ቢోߥࠄ߫‫ޔ‬ዞᬺᓟߦࡒࠬࡑ࠶࠴߇ේ࿃ߢ㔌⡯ߔࠆߎߣߪߥ޿‫ߚ߹ޕ‬ቢో┹੎ߩ઒ቯߢߪ‫ޔ‬ડᬺߪഭ௛⠪ߩ⢻ജߦᔕߓߚ⾓㊄ߒ߆ᡰᛄࠊߥ޿‫ޕ‬ㅒߦᖱႎ߇ਇቢోߢ޽ࠆߥ
ࠄ߫‫ޔ‬ዞ޿ߡߺߡวࠊߥ޿⡯ߢ޽ߞߚ႐วߪ㔌⡯߽⿠ߎࠅ߁ࠆ‫ߚ߹ޕ‬ഭ௛⠪ߪߤߩડᬺ߇ߤ
ࠇߛߌߩ⾓㊄ࠍᛄߞߡ޿ࠆ߆ಽ߆ࠄߥ޿ߚ߼ߦ‫ࠅࠃޔ‬㜞޿⾓㊄ࠍ᳞߼ߡ⡯ࠍតߔߎߣߦߥࠆ‫ޕ‬ઁᣇ‫ޔ‬ડᬺߩ஥߽ഭ௛⠪ߩ㒢⇇↢↥ജએ਄ߩ㜞޿⾓㊄ࠍឭ␜ߔࠇ߫‫ࠅࠃޔ‬ᄙߊߩഭ௛⠪ࠍᒁ߈ઃߌࠆ੐߇ߢ߈ࠆ‫⾓ߒ߆ߒޕ‬㊄ߩ㜞ૐߦ㑐ࠊࠄߕ‫ࠆ޽ޔ‬⒟ᐲߩ㔌⡯ߪㆱߌࠄࠇߥ޿‫ޕ‬ߎߎߢ‫ޔ‬ડᬺߩᣂⷙណ↪㊂ࠍ᳿ቯߠߌࠆ㑐ᢙࠍ H(w)‫ޔ‬ഭ௛⠪ߩ㔌⡯₸ߩ㑐ᢙࠍ q(w)ߣ‫ޔ‬ߘࠇߙࠇࠍ⾓㊄ w ߩ㑐ᢙߢ޽ࠄࠊߔ‫ޔߚ߹ޕ‬ឭ␜⾓㊄߇਄߇ࠇ߫‫ޔ‬㓹↪ߢ߈ࠆᢙߪჇ߃‫ޔ‬㔌⡯₸ߪᷫࠆ߽ߩߣߔࠆ‫ޕ‬ဋⴧߢߪᒰᦼߦ㓹޿౉ࠇߚᢙߣ㔌⡯⠪ᢙ߇৻⥌ߔࠆ‫ࠅ߹ߟޔ‬H(w) = q(w)L(4),ࠍḩߚߔᔅⷐ߇޽ࠆ‫ ߢߎߎޕ‬L ߪડᬺߩੱຬᢙߢ޽ࠆ‫ࠍࠇߎޕ‬ᄌᒻߒߚL = H(w) / q(w)(5),߇ડᬺߩ⋥㕙ߔࠆഭ௛ߩଏ⛎㑐ᢙߣߥࠅ‫⾓ޔ‬㊄ w ߩ⺞▵ߢ㓹↪㊂ࠍჇᷫߢ߈ࠆ‫ޕ‬㓹↪⠪ߩ㔌⡯߇⿠ߎࠆߚ߼‫ޔ‬ဋⴧ㓹↪㊂ L*ࠍታ⃻ߔࠆߦߪ‫ޔ‬ડᬺߪ㜞޿⾓㊄ࠍឭ␜ߒߡࠃࠅᄙߊߩഭ௛
⠪ࠍᒁ߈ઃߌߡ߅ߊᔅⷐ߇޽ࠆ‫⾓ޔߚ߹ޕ‬㊄ߩჇടߦኻߒߡ‫ޔ‬H ߪჇട‫ޔ‬q ߪᷫዋߔࠆߩߢ
ଏ⛎㑐ᢙ L(w)ߪ‫⾓ޔ‬㊄ߩჇട㑐ᢙߣߥࠆ‫(ޕ‬5)ᑼࠍഭ௛ଏ⛎ߩ⾓㊄ᒢജᕈ⴫␜ߦᡷ߼ࠆߣ‫ޔ‬
ǯ= dlogL / dlogw = ǰ H – |ǰq|(6),ߣߥࠆ‫ޕ‬ǰ H ߪ㓹↪ߩ⾓㊄ᒢജᕈ‫ޔ‬ǰq ߪ㔌⡯₸ߩ⾓㊄ᒢജᕈߢ޽ࠆ㧔ǰq㧨0㧕‫ޕ‬ǰH‫޿ࠆ޽ޔ‬ߪ|ǰq㨨߇ᄢ߈޿߶ߤ‫ޔ‬ഭ௛ଏ⛎ߩ⾓㊄ᒢജᕈ߽ᄢ߈޿ߎߣߦߥࠆ‫⾓ߦ߆ߕࠊޔࠅ߹ߟޕ‬㊄ࠍ਄᣹ߐߖߚߛߌߢ൐㓸߇ᄙߊ㓸߹ࠆ߆‫ߪ޿ࠆ޽ޔ‬㔌⡯㒐ᱛലᨐ߇ᄢ߈޿႐วߪ‫ޔ‬ဋⴧ㓹↪
㊂ L*ࠍ⏕଻ߔࠆߚ߼ߦᔅⷐߥ㒢⇇⊛ߥ⾓㊄Ⴧട߽ዋߥߊߡߔ߻ߎߣߦߥࠆ‫ޕ‬ߎߩࡕ࠺࡞߆ࠄዉ߆ࠇࠆࠗࡦࡊ࡝ࠤ࡯࡚ࠪࡦߦߟ޿ߡ‫ޔ‬Card and Krueger (1995) ߪᰴߩὐࠍ᜼ߍߡ޿ࠆ‫ੱޔߕ߹ޕ‬ຬⷙᮨ߇ᄢ߈޿ડᬺ߶ߤ‫ޔ‬ᔅⷐߥੱຬࠍᣂߚߦ⏕଻ߔࠆߚ߼ߩណ
↪ࠦࠬ࠻ߪჇടߔࠆ‫ޕ‬Katz and Krueger (1992) ߿ Card and Krueger (1995) ߩታ⸽⚿ᨐߪ‫ޔ‬㧙㧙ੱຬⷙᮨߩᄢ߈޿ᐫ⥩߇㜞޿⾓㊄ࠍᛄߞߡ޿ࠆߎߣࠍ␜ߒߡ߅ࠅ‫ߩ࡞࠺ࡕޔ‬ᚑ┙ࠍᡰᜬߒߡ
޿ࠆ‫ޕ‬ੑߟ⋡ߪ‫ޔ‬ㆡᐲߥᦨૐ⾓㊄ߩ਄᣹ߢ޽ࠇ߫㓹↪㊂ߪჇ߃ࠆ‫⁛ߩ⥸৻ޔߪࠇߎޕ‬භࡕ࠺࡞ߢ␜ߒߚߣ߈ߣห᭽ߩ⚿⺰ߢ޽ࠆ‫(ޕ‬5)ᑼࠃࠅ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߚ႐ว‫ޔ‬ડᬺߪᄙߊߩഭ
௛⠪ࠍ㓹߁ߎߣ߇น⢻ߦߥࠆ‫ᦨޔߒ߽ޕ‬ૐ⾓㊄ߩ਄᣹߇✭߿߆ߢ޽ࠇ߫‫ޔ‬ડᬺߪଏ⛎ߐࠇߚഭ௛ജࠍߔߴߡᵴ↪ߔࠆߎߣߦߥࠆ‫ᦨޔߒ߆ߒޕ‬ૐ⾓㊄ߪᣢߦ㓹↪ߐࠇߡ޿ࠆഭ௛⠪ߦኻߒߡ߽ㆡ↪ߐࠇࠆ‫ᦨޔ߃ࠁࠇߘޕ‬ૐ⾓㊄߇ᕆỗߦ਄᣹ߒߚ႐วߦ(5)ߢታ⃻ߐࠇࠆഭ௛ജࠍ㓹߃߫‫⾓ߩߘޔ‬㊄߇ഭ௛⠪ߩ㒢⇇෼౉↢↥‛㧔MRP㧕ߩ୯ࠍ⿥߃ߡߒ߹߁‫ޔ߈ߣߩߎޕ‬ડᬺߪഭ௛⠪ߩ㒢⇇෼౉↢↥‛㧔MRP㧕ߩ୯ߣᦨૐ⾓㊄㗵ࠍ৻⥌ߐߖࠆߚ߼‫ޔ‬㓹↪㊂ࠍ೥ᷫߔࠆߎߣ
ߦߥࠆ‫ޕ‬

 ഭ௛ߩ⇣⾰ᕈ਄⸥ߩቢో┹੎ࡕ࠺࡞‫ߪ޿ࠆ޽ޔ‬㔛ⷐ⁛භࡕ࠺࡞ߪ‫ޔ‬Ꮢ႐ߦෳടߒߡ޿ࠆഭ௛⠪߇⊝‫ޔ‬ห⾰ߢ޽ࠆߣ઒ቯߐࠇߚ߽ߩߢ޽ࠆ‫ޔࠄ߇ߥߒ߆ߒޕ‬ഭ௛⠪ߩᛛⴚ᳓ḰߦߪᏅ߇޽ࠅ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߚ႐ว‫⋥ޔ‬ធ⊛ߦ⾓㊄޽ࠆ޿ߪ㓹↪ߦᓇ㗀ࠍฃߌࠆߩߪᛛⴚ᳓Ḱߩૐ޿ૐ⾓㊄ഭ௛⠪ߢ޽ࠆ‫ޕ‬਄⸥ੑࡕ࠺࡞ߪ‫ࠆ޽ޔ‬ᛛⴚ᳓Ḱࠍ᦭ߔࠆഭ௛⠪߇ෳടߒߡ޿ࠆ․ቯߩഭ௛Ꮢ႐
ߩࠬ࠽࠶ࡊ౮⌀ߦㆊ߉ߥ޿‫ޕ‬࿖߿࿾ၞߥߤߦ߅ߌࠆో૕ߩഭ௛Ꮢ႐ࠍ⠨߃ࠆߥࠄ߫‫ޔ‬ഭ௛⠪ߩᛛⴚ᳓ḰߦᔕߓߡᏒ႐ࠍಽߌࠆᔅⷐ߇޽ࠆ‫ޕ‬ഭ௛⠪ߩ⇣⾰ᕈࠍ⠨ᘦߒߚᦨ߽න⚐ߥࡕ࠺࡞ߪ‫ޔ‬ᛛⴚ᳓Ḱߩૐ޿ഭ௛⠪ߣᾫ✵ഭ௛⠪ߩੑ࠲ࠗࡊ߇ഭ௛Ꮢ႐ߦෳടߒߡ޿ࠆ߽ߩߢ޽ࠈ߁‫ޕ‬ߎߩੑ࠲ࠗࡊߩഭ௛⠪ࠍ⠨ᘦߒߚࡕ࠺࡞ߪ‫ޔ‬వߩቢో┹੎ࡕ࠺࡞ߦ߅ߌࠆ⾗ᧄߣഭ௛ߩ↢↥ⷐ⚛㑆ߩ㑐ଥߣ‫⺰ߩߘޔ‬ℂߪ߶ߣࠎߤหߓߢ޽ࠆ‫ޔߡߒߣ⚛ⷐ↥↢ޔࠅ߹ߟޕ‬ੑ⒳㘃ߩഭ௛ᛩ౉ࠍ⠨ᘦߒߚߦㆊ߉ߥ޿‫ߩߎޔߛߚޕ‬ഭ௛ߩੑಽഀࡕ࠺࡞ߪ‫ޔ‬ᓟㅀߔࠆᤨ♽೉ಽᨆ╬ߩၮ␆ߦߥࠆࡕ࠺࡞ߢ޽ࠆߚ߼‫ޔ‬ᡷ߼ߡએਅߦ⸅ࠇࠆߎߣߦߒߚ޿‫ޕ‬ࡕ࠺࡞ߩ઒ቯߢߪ‫ᦨޔ‬ૐ⾓㊄ᒁ߈਄ߍ೨ߩ㕖ᾫ✵ഭ௛⠪ߩ⾓㊄ߪ‫ᦨޔ‬ૐ⾓㊄ᡷᱜᓟߩᦨૐ
⾓㊄ߩ᳓Ḱࠃࠅૐߊ⸳ቯߐࠇࠆ‫ᦨߡߞࠃޕ‬ૐ⾓㊄ߩᒁ߈਄ߍߦࠃߞߡ‫ޔ‬㕖ᾫ✵ഭ௛⠪ߩ⾓㊄ߪᓇ㗀ࠍฃߌࠆ‫ઁޕ‬ᣇ‫ᦨޔ‬ૐ⾓㊄ᒁ߈਄ߍ೨ߦ߅ߌࠆᾫ✵ഭ௛⠪ߩ⾓㊄ߪᒁ߈਄ߍᓟߩᦨૐ
⾓㊄ࠃࠅ㜞ߊ‫ᦨޔ‬ૐ⾓㊄ߩᒁ߈਄ߍߦࠃࠅᓇ㗀ࠍฃߌߥ޿߽ߩߣߔࠆ‫ޔߦࠄߐޕ‬ᾫ✵ഭ௛⠪ߩᛛⴚߪ㕖ᾫ✵ഭ௛⠪ߩᛛⴚࠍ߽ߞߡቢోߦઍᦧߢ߈ߥ޿߽ߩߣߔࠆ‫ᦨޕ‬ૐ⾓㊄਄᣹߇㕖ᾫ✵ഭ௛⠪ߩ㓹↪ߦਈ߃ࠆᓇ㗀ߪ‫ޔ‬వߩቢో┹੎ߩ႐วߣห᭽ߩ߽ߩߦߥࠅ‫ޔ‬㓹↪ࠍᷫࠄߔᣇ
ะߦ௛ߊ‫ߩߘޕ‬ᷫዋ᏷ߪ‫ߦ↪⾌✚ޔ‬භ߼ࠆ㕖ᾫ✵ഭ௛ߩੱઙ⾌╬ߦࠃߞߡ᳿߹ߞߡߊࠆ‫ઁޕ‬ᣇ‫ޔ‬ᾫ✵ഭ௛⠪ߦਈ߃ࠆᓇ㗀ߪ৻᭎ߦ⺰ߕࠆߎߣߪߢ߈ߥ޿‫↥↢ޔߒ߽ޕ‬ᛛⴚ߇ᾫ✵ഭ௛⠪ߩഭ௛ߣ㕖ᾫ✵ഭ௛ߣߩઍᦧࠍ޽ࠆ⒟ᐲ⸵ߔߥࠄ‫↥ޔ‬಴㊂৻ቯߩ߽ߣߢߪ‫ޔ‬ᾫ✵ഭ௛⠪ߩ㓹↪ߪჇടߔࠆ‫ޔߒ߆ߒޕ‬ਔഭ௛ജ߇⵬ቢߒ޽ߞߡ↢↥ࠍⴕߞߡ޿ࠆߥࠄ߫‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߪ‫ޔ‬ᾫ✵ഭ௛ജߩ㓹↪㊂ߦ߽⽶ߩᓇ㗀ࠍਈ߃ࠆߎߣߦߥࠆ‫ᦨߡߞࠃޕ‬ૐ⾓㊄ߩ਄᣹߇‫ޔ‬ᾫ✵ഭ௛⠪ߣ㕖ᾫ✵ഭ௛⠪‫ߩߘޔ‬ਔ⠪ࠍวࠊߖߚో㓹↪㊂ߦਈ߃ࠆᓇ㗀ߪਇ᣿ߢ޽ࠆ‫ޔߒߛߚޕ‬ઁߩ↢↥ⷐ⚛ߣߒߡߩ⾗ᧄ߇‫ޔ‬㕖ᾫ✵ഭ௛ߩઍࠊࠅࠍⴕ߃ࠆߩߢ޽ࠇ߫‫ోޔ‬㓹↪㊂߽ᷫዋߔ㧙㧙ࠆߎߣߦߥࠆ‫ޕ‬ߒ߆ߒ‫ߩߎޔ‬ᾫ✵‫ޔ‬㕖ᾫ✵ߩੑಽഀࡕ࠺࡞ߢ߽‫ߩࠅߥ߆ޔ‬න⚐ൻ߇ߥߐࠇߡ޿ࠆߎߣߪ⸒
߁߹ߢ߽ߥ޿‫ޔߒߛߚޕ‬ర᧪‫ޔ‬ᛛⴚ᳓Ḱߪㅪ⛯⊛ߥ߽ߩߢ޽ࠆߚ߼‫ޔ‬᳓ḰߏߣߦᏒ႐ࠍಽߌ
ߡ৻ߟ৻ߟߘߩᄌൻࠍ⷗ߡ޿ߊߎߣߪਇน⢻ߢ޽ࠆ‫ᦨޔߢߎߘޕ‬ૐ⾓㊄ߩᵄ෸ലᨐࠍᬌ⸽ߒ
ߚታ㓙ߩታ⸽ಽᨆߢߪ‫ోޔ‬૕ߩ⾓㊄ಽᏓߢߘߩലᨐࠍᛠីߒߡ޿ࠆ߽ߩ߇޽ࠆ‫ᦨޔࠅ߹ߟޕ‬ૐ⾓㊄਄᣹೨ᓟߩಽᏓᄌൻࠍ‫ᦨޔ‬ૐ⾓㊄ࠍ਄᣹ߐߖߚߎߣߦࠃࠆഭ௛⠪ߩ⾓㊄ߣ㓹↪߳ߩᓇ㗀ߣᝒ߃ߡ޿ࠆ‫ޔߚ߹ޕ‬ㅢᏱ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߔࠆ೨ߦ୘ੱ߇ฃߌขߞߡ޿ߚ⾓㊄㗵ߩ㆑޿߇‫ޔ‬ᛛⴚ᳓Ḱߩ㆑޿ߢ޽ࠆߣ઒ቯߐࠇࠆ‫ߩࠞ࡝ࡔࠕޕ‬ታ⸽⎇ⓥߢߪ‫ᦨޔ‬ૐ⾓㊄㗵ߜࠂ߁ߤߢ
㓹↪ߐࠇࠆ⠪ߩഀว߇‫ߩߘޔ‬๟ㄝߩ⾓㊄ߢ㓹ࠊࠇߡ޿ࠆ⠪ߩഀวࠃࠅᄢ߈޿ߎߣ߇ⷰኤߐࠇ
ߡ޿ࠆ‫ߣࠢࠗࡄࠬࠆࠁࠊ޿ޕ‬๭߫ࠇࠆ⃻⽎ߢ޽ࠅ‫৻ޔ‬ㇱഭ௛⠪ߩ⾓㊄ࠍᐩ਄ߍߒߡ޿ࠆߎߣ
ߦߥࠆ‫ޔߪߡ޿ߟߦߣߎߩߎޕ‬ᓟ▵ߦߡ◲නߦㅀߴࠆߎߣߦߔࠆ‫ޕ‬ ⑔೑ෘ↢⾌╬ߩ⋧Ვડᬺߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ಽࠍ⑔೑ෘ↢⾌‫ߪ޿ࠆ޽ޔ‬ᢎ⢒⸠✵⾌╬߆ࠄᏅߒᒁߊน⢻ᕈ߽޽ࠆ‫ߩߎޕ‬႐ว‫⾓ޔ‬㊄ࠍ㕖㊄㌛⊛⾌↪ߩᷫዋߢ⋧Ვߔࠆߎߣߦࠃࠅ‫ᦨޔ‬ૐ⾓㊄਄᣹೨ߩ㓹↪㊂ࠍ⏕଻ߔࠆഭ௛㔛ⷐࠍ⛽ᜬߔࠆߎߣߪߢ߈ࠆ‫ޔࠄ߇ߥߒ߆ߒޕ‬ഭ௛⠪߇⑔೑ෘ↢⾌ߥߤ㕖㊄㌛⊛ߥႎ㈽߆ࠄฃߌขࠆല↪ߣ‫↪૶ޔ‬⠪߇⽶ᜂߔࠆ⾌↪ߪ৻⥌ߒߥ޿߆߽ߒࠇߥ޿‫ޕ‬ᄙߊߩ႐ว‫⑔ޔ‬೑ෘ↢⾌ߪⷙᮨߩ⚻ᷣᕈ߇௛ߊߚ߼ߦ‫ޔ‬୘ੱߢߘߩ⾌↪ࠍ⽶ᜂߔࠆߣડᬺ߇⽶ᜂߔࠆ႐วࠃࠅ㜞ߊߟߊ‫↪૶ߚ߹ޕ‬⠪ߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߒߚಽ‫ޔ‬ഭ௛⠪ߦኻߒߡࠃࠅ㜞޿ࡁ࡞ࡑࠍ⺖ߔ߆߽ߒࠇߥ޿‫ߪࠇߎޕ‬ഭ௛⠪ߩਇല↪ࠍჇߔߎߣߦߥࠆ‫ᦨߡߞࠃޕ‬ૐ⾓㊄ߩ਄᣹ಽࠍઁߩ߽ߩߢ⋧Ვߒࠃ߁ߣߔࠆߣ‫ޔ‬ഭ௛ଏ⛎㊂ߪᷫዋߔࠆน⢻ᕈ߇ߢࠆ‫ߦࠄߐޕ‬ല₸⾓㊄઒⺑ߩⷰὐߦ┙ߡ߫‫ޔ‬૞ᬺⅣႺߩᖡൻ߿⑔೑ෘ↢⾌ߩ೥ᷫߪ‫ޔ‬ഭ௛⠪ߩ૞ᬺല₸ࠍ⪭ߣߔน⢻ᕈ߽޽ࠆ‫ޔߡߞࠃޕ‬ડᬺߦߣߞߡ⋧Ვߣ޿߁ⴕὑ߇วℂ⊛ߥⴕേ߆ߤ߁߆ߪ‫ޔ‬వ⷗⊛ߦߪ⸒߁ߎߣ߇ߢ߈ߥ޿‫☨ߦߺߥߜޕ‬࿖ߩࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼ᐫߢߪ‫ޔ‬㘩੐ࠍήᢱ߆ૐଔᩰߢឭଏ
ߔࠆᒻߢ⑔೑ෘ↢߇ⴕࠊࠇߡ޿ࠆ߇‫ᦨޔ‬ૐ⾓㊄਄᣹ᓟߦߘߩࠨ࡯ࡆࠬ߇ขࠅ߿߼ߦߥߞߚ੐
ታߪߥ޿ࠃ߁ߢ޽ࠆ (Card and Krueger (1995))‫⧯ޔߒ߆ߒޕ‬ᐕጀߩ OJT ࠦࠬ࠻ߦ㑐ߒߡߪ‫ޔ‬
ᦨૐ⾓㊄ߩ਄᣹ߦࠃࠅ‫ߩߘޔ‬ᄙߊ߇ᷫዋߒߚߣߩታ⸽⎇ⓥ (Neumark and Wascher (2001))
߇಴ߡ޿ࠆ 1‫ޕ‬㧞 ☨࿖ߩታ⸽⎇ⓥ ᭎ⷐ
วⴐ࿖᡽ᐭߪ‫ޔ‬1981 ᐕߦㅪ㇌ᦨૐ⾓㊄ࠍ 3.35 ࠼࡞ߦᒁ߈਄ߍߡએ㒠‫ޔ‬1980 ᐕઍࠍㅢߒߡ

1

Hashimoto (1982) ߽⊕ੱ↵ᕈߩ OJT ࠦࠬ࠻߇ᷫዋߒߚߎߣࠍታ⸽ߒߡ޿ࠆ‫ޔࠄ߇ߥߒ߆ߒޕ‬ᓐߩᚻᴺߪ‫⾓ޔ‬㊄ࡊࡠࡈࠔࠗ࡞ߦᦨૐ⾓㊄߇ਈ߃ࠆᓇ㗀ࠍ⠨ᘦߒߡ޿ߥ޿ὐࠍ Neumark and Wascher (2001) ߦࠃߞߡᛕ್
ߐࠇߡ޿ࠆ‫ޕ‬㧙㧙ㅪ㇌ᦨૐ⾓㊄ࠍ‫ߩߘޔ‬᳓Ḱߦᝪ߃⟎޿ߡ޿ߚ‫ޔߒ߆ߒޕ‬1990 ᐕߦㅪ㇌⾓㊄߇ 3.80 ࠼࡞ߦᒁ߈޽߇ࠆߣ‫ߩߘޔ‬ᓟߩ 90 ᐕઍߪ‫ޔ‬80 ᐕઍߣኻᾖ⊛ߦ‫ޔ‬ㅪ㇌ᦨૐ⾓㊄߇Ბ㓏⊛ߦᒁ߈਄ߍࠄ
ࠇߡ޿ߊߎߣߦߥࠆ‫ޕ‬1990 ᐕઍߩᐲ㊀ߥࠆᒁ߈਄ߍࠍᄾᯏߦ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦߤߩࠃ߁ߥ‫ޔ‬߹ߚ‫ߩߤ߶ࠇߤޔ‬ᓇ㗀ࠍਈ߃ࠆ߆ߣ޿߁⼏⺰߇‫ޔ‬ౣ߮⚻ᷣቇ⠪ߩᵈ⋡ࠍᶎ߮ࠆࠃ߁ߦߥࠆ‫ޕ‬ߣࠅࠊߌ‫ߩ⺰⼏ޔ‬ྊ⍫ߣߥࠆ Card (1992a, 1992b)‫ޔ‬Katz and Krueger (1992) ߪ‫⚿ޔ‬ᨐߩࠗࡦࡄࠢ࠻߆ࠄᄙߊߩ⺰੎ࠍᒁ߈⿠ߎߒߚ‫ޕ‬ᓐࠄߩታ⸽⚿ᨐߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹߇‫ߩߘޔ‬ᓇ㗀ࠍฃߌࠆഭ௛⠪ߩ㓹↪㊂ࠍࠊߕ߆ߥ߇ࠄჇ߿ߔᣇะߦ௛ߊ߆‫ߤࠎߣ߶ޔ‬ᓇ㗀ࠍਈ߃ߥ޿ߣ
ߒߚ‫ޕ‬਄⸥⺰ᢥߩ⊒⴫߹ߢ‫⚻ޔ‬ᷣቇ⠪ߩ߶ߣࠎߤ߇‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߪ㓹↪༚ᄬലᨐࠍᜬߟߣ⠨߃ߡ޿ߚ‫ޕ‬ታ㓙‫ޔ‬1980 ᐕઍ߹ߢߩ࠺࡯࠲ࠍ↪޿ߚಽᨆߢߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߦࠃࠅ㓹↪㊂߇ᷫዋߔࠆߎߣ߇৻᭽ߦ␜ߐࠇߡ޿ࠆ 2‫⺰ߩࠄࠇߎޕ‬ᢥߢ↪޿ࠄࠇߡ߈ߚᚻᴺߪ‫♽ᤨޔ‬೉ಽᨆ߇ਛᔃߢ޽ࠆ‫ޕ‬ഭ௛⚻ᷣቇߩಽ㊁ߢߪ‫♽ᤨޔ‬೉ಽᨆߢ৻⥸ߦ↪޿ࠄࠇࠆࠃ߁ߥ㓸⚂ߐࠇߚ࠺࡯
࠲ࠍ૶߁ߎߣߦߟ޿ߡ‫ޔ‬᭽‫ߥޘ‬໧㗴ὐ߇ᜰ៰ߐࠇߡ޿ࠆ (Stafford (1986))‫ߩ࠲࡯࠺ޕ‬೙⚂߆ࠄ‫☨ޔ‬࿖ߢᦨૐ⾓㊄߇⼏⺰ߐࠇࠆ㓙ߪ‫ޔ‬ଐὼߣߒߡᤨ♽೉ಽᨆ߇ਥᵹߦߥࠄߑࠆࠍᓧߥ߆ߞ
ߚߩߢ޽ࠆ‫♽ᤨޔߒ߆ߒޕ‬೉ಽᨆߩ⺰ᢥߢߪ‫ߩߘޔ‬ᄢ߈ߐߦߟ޿ߡߪ⧯ᐓ߫ࠄߟ߈߇޽ࠆ߽
ߩߩ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦኻߒߡ⽶ߩᓇ㗀ࠍᜬߟߎߣ߇‫଀ޔ‬ᄖήߊ␜ߐࠇߡ޿ࠆ‫߇ࠇߘޕ‬቟ቯߒߚ⚿ᨐߢ޽ࠆߣᝒ߃ࠄࠇࠆߩ߽‫ޔ‬ήℂߪߥ޿‫ߩߘޔߦ߃ࠁޕ‬㓹↪༚ᄬലᨐࠍ␜ߒߚࠗࡦࡊ
࡝ࠤ࡯࡚ࠪࡦߪ‫ᦨޔ‬ૐ⾓㊄ߩലᨐࠍ⼏⺰ߔࠆ㓙‫ޔ‬ቇ⇇ߩߺߥࠄߕ᡽⇇߿ⴕ᡽ߦ߽‫ޔ‬㐳޿㑆ᄢ߈ߥᓇ㗀ജࠍᜬߜ⛯ߌߡ߈ߚ‫ޕ‬ᄙߊߩ໧㗴ࠍᛴ߃ࠆᤨ♽೉ಽᨆߦኻߒ‫ޔ‬1990 ᐕઍߦ౉ࠅឭ಴ߐࠇߚ Card ࠄߩᦨૐ⾓㊄ߦߪ㓹↪༚ᄬലᨐ߇ߥ޿ߣߒߚಽᨆߪ‫ࠍ࠲࡯࠺࡮࡞ࡀࡄޔ‬ਥߦ૶↪ߒߚ߽ߩߢ޽ࠆ‫ޔߚ߹ޕ‬Ყセࠣ࡞࡯ࡊࠍ↪޿ߚ⥄ὼ⑼ቇߩታ㛎ߐߥ߇ࠄߩಽᨆ߽ⴕࠊࠇߡ޿ࠆ‫ߦ߁ࠃߩߎޔߛߚޕ‬ᵞ✵
ߐࠇߚᚻᴺࠍ↪޿ߚߦ߽㑐ࠊࠄߕ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦ⽶ߩᓇ㗀ࠍਈ߃ࠆߣ޿߁⚻ᷣቇ⠪ߩ⠨߃ࠍ‫ޔ‬ቢోߦߪᛄ᜞ߢ߈ߥ߆ߞߚ‫ޕ‬Neumark and Wascher (1992) ߣߘࠇߦ⛯ߊᓐࠄߩ⺰ᢥ߇‫ޔ‬ห᭽ߦࡄࡀ࡞࡮࠺࡯࠲ࠍ↪޿ߡ‫ᦨޔ‬ૐ⾓㊄߇㓹↪㊂ߦ⽶ߩᓇ㗀ࠍਈ߃ࠆߎߣࠍ␜ߒߚ߆
ࠄߢ޽ࠆ‫ޕ‬ᓐࠄߪ‫ᦨޔ‬ૐ⾓㊄ߩലᨐࠍ⸘ࠆ㓙‫ޔ‬ዞቇ₸ߩᨐߚߔᓎഀ߇㊀ⷐߢ޽ࠆߣߒߡ޿ࠆ‫ޕ‬
ߐࠄߦ Neumark and Wascher (1995a, 1995b) ߢߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߦࠃߞߡ‫ޔ‬ቇᩞࠍㄉ߼
ߡ⡯ߦዞߊ⠪ߩഀว߇㜞߹ࠆ‫ޕ‬ㅒߦ‫ޔ‬ᡷᱜᦨૐ⾓㊄ࠃࠅ߽ૐ޿⾓㊄ߢ௛޿ߡ޿ߚഭ௛⠪ߩ߁ߜ‫ޔ‬ቇᩞߦⴕߞߡ޿ߥ߆ߞߚ⠪ߪ‫ߩߘޔ‬ዞᬺᯏળ߇៊ߥࠊࠇߚߎߣ߇ႎ๔ߐࠇߡ޿ࠆ‫ޕ‬
Card ࠄߩ⺰ᢥߦߒࠈ Neumark ࠄߩߘࠇߦߒࠈ‫ޔ‬ផ⸘ߦ㓙ߒߡ޿ߊߟ߆ߩ㔍ὐࠍ᦭ߒߡ޿
ࠆ‫ߩߘޔߚ߹ޕ‬ὐࠍઍᦧ⊛ߥᣇᴺߢ⵬ᱜߔࠆߣ‫ᦨޔ‬ૐ⾓㊄ߩ㓹↪ߦਈ߃ࠆᓇ㗀ߩ╓ว߇ㅒߦߥࠆߎߣ߇‫ᦨޔߌߛࠇߘޕࠆ޽߹߹ޔ‬ૐ⾓㊄߇㓹↪ߦਈ߃ࠆലᨐߪᓸᅱߥ߽ߩߢ޽ࠆߣ⸒߃
ࠃ߁‫ᦨޔߦ߃ࠁޕ‬ૐ⾓㊄ߩ㓹↪༚ᄬലᨐߪ‫ޔ‬ታ⸽⎇ⓥߩಽ㊁ߦ߅޿ߡ‫ߛ߹޿ޔ‬᳿⌕ࠍ⷗ߡ޿

2

Brown (1999) ߦߪ‫ޔ‬ㆊ෰ߩታ⸽⚿ᨐ߇◲ẖߦ߹ߣ߼ࠄࠇߡ޿ࠆ‫ޕ‬㧙㧙ߥ޿ߩ߇ታᖱߢ޽ࠆ‫ޕ‬ᧄ▵ߢߪએਅߦ‫♽ᤨޔ‬೉ಽᨆߣࡄࡀ࡞ಽᨆߩ⚿ᨐߣߘߩ໧㗴ὐࠍ‫ᤨޕࠆߔ੺⚫ࠇߙࠇߘޔ‬♽೉ಽᨆߪ‫ߦ߆⏕ޔ‬ᄙߊߩ໧㗴ࠍ᦭ߒߡ޿ࠆ‫ߒ߆ߒޕ‬ಽᨆߩ⢛ᓟߦ޽ࠆ᭎ᔨߪ‫ߩߘޔ‬ᓟߩࡄࡀ࡞࡮࠺࡯࠲ಽᨆߦ‫߹߹ߩߘޔ‬ฃߌ⛮߇ࠇߡ޿ࠆߚ߼‫ߊߒ⹦ߡ߃޽ߪߢ▵ᧄޔ‬ㅀߴࠆߎߣߦߔࠆ‫ޕ‬ ᤨ♽೉ಽᨆ
ࠕ ᚻᴺߣ໧㗴ὐᤨ♽೉ಽᨆߦࠃࠆផ⸘ߪ‫ߦ⊛⥸৻ޔ‬એਅߩࠃ߁ߥන৻ߩ࿁Ꮻᑼࠍ↪޿ߡ‫ᦨޔ‬ૐ⾓㊄ߩലᨐࠍ⸘᷹ߒߡ޿ࠆ‫ޕ‬
Et = ǩXt + ǪMWt + ǭt

(7),

ߎߎߢ Et ߪ t ᦼߩഭ௛⠪ᢙ‫ޔ‬X ߪ᥊᳇ᓴⅣ╬ࠍ⴫ߔઍℂᜰᮡ‫ޔ‬MW ߪᦨૐ⾓㊄ߩ㗵ࠍ␜ߔᜰᮡߢ޽ࠆ‫ޔߚ߹ޕ‬ǭt ߪ⺋Ꮕ㗄ߢ޽ࠆ‫ޕ‬Brown et al (1982, 1983) ߢᜰ៰ߐࠇߡ޿ࠆࠃ߁ߦ‫ޔ‬㔛ⷐ஥ߩⷐ࿃ߢ޽ࠆ X ߪᄙߊߩ⺰ᢥߢ౒ㅢߒߡዉ౉ߐࠇߡ޿ࠆ‫ੱ߫߃଀ޔߒ߆ߒޕ‬ญ᭴ᚑᲧߥߤ‫ޔ‬ଏ⛎஥ߩⷐ࿃ߣߒߡ‫ⷐߩߤޔ‬࿃ࠍណ↪ߒߡ޿ࠆ߆ߪฦ⺰ᢥߦࠃߞߡ⇣ߥࠆ‫ߩߘޕ‬ℂ↱
ߣߒߡߪ‫ޔ‬1)‫ޔ‬ቢో┹੎ࡕ࠺࡞ߦᓥ߃߫‫ᦨޔ‬ૐ⾓㊄਄᣹ᓟߩ㓹↪㊂ߪ‫ޔ‬⍴ᦼ⊛ߦߪ㔛ⷐ஥ߩ೙⚂ߦࠃߞߡ᳿߹ࠆߩߢ‫ޔ‬ଏ⛎஥ߩⷐ࿃ߪᭂജ‫⺑ޔ‬᣿ᄌᢙߦ౉ࠇࠆߴ߈ߢߪߥ޿‫ޕ‬2)‫ᦨޔ‬ૐ
⾓㊄߇ሽ࿷ߒߥߌࠇ߫‫ޔ‬㔛ⷐ㊂ߣଏ⛎㊂ߪဋⴧߒߡ޿ߚߎߣߦߥࠆ‫ޕ‬ഭ௛ߩ⿥ㆊଏ⛎߇⊒↢ߒߚ႐ว‫ߪࠇߘޔ‬ᄖ↢⊛ߥ߽ߩߢߪߥߊ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߚߎߣߩᓇ㗀ߣ޿߃ࠆ‫ޔߡߞࠃޕ‬ଏ⛎஥ߩⷐ࿃ࠍਇ↪ᗧߦᝌ౉ߒߡផቯࠍⴕ߁ߣ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦਈ߃ࠆᓇ㗀ࠍᱜ⏕ߦ⸘᷹ߢ߈ߥ޿‫ߚߞ޿ߣޔ‬ὐ߇޽ߍࠄࠇߡ޿ࠆ‫ޕ‬ߚߛߒ‫ߩߘޔ‬ᛒ޿ߦߪ᳇ࠍઃߌߨ߫ߥࠄߥ޿߽ߩߩ‫ޔ‬ផቯߦ㓙ߒߡㆡಾߥഭ௛ଏ⛎஥ߩⷐ࿃ࠍ฽߼‫ޔ‬ផቯᑼࠍࠦࡦ࠻ࡠ࡯࡞ߔࠆߎߣߪ㊀ⷐߢ޽ࠆ‫⺑ⵍޔߪࠇߘޕ‬᣿ᄌᢙߩ E ߦ㓹↪⠪ᢙࠍ↪޿ߥ޿႐ว߇ᄙߊ‫ߩߘޔ‬႐ว(7)ᑼ߇⚐☴ߥഭ௛㔛ⷐ㑐ᢙߣߥࠄߥ޿߆ࠄߢ޽ࠆ‫ޕ‬ㅢᏱ‫ޔ‬ᤨ♽೉ಽᨆߢ E ߣߒߡ↪޿ࠄࠇࠆߩߪ‫ޔ‬10 ઍᓟඨ㧔16㧙19 ᱦ㧕ߩ㓹↪⠪ࠍ‫࡯ࡎ࡯ࠦߩߘޔ‬࠻ੱญߢഀߞߚ୯ߢ޽ࠆ‫ ߦઁߩߎޕ‬20 ઍ೨ඨߩ⧯ᐕጀࠍ฽߼ߚᒻߢផቯߔࠆߥߤ‫ޔ‬ᐕ㦂ߩ඙ಾࠅߪฦ⺰ᢥߦࠃߞߡᄙዋߩ߫ࠄߟ߈߇޽ࠆ‫(ޔߒ߽ޕ‬7)ᑼࠍഭ௛㔛ⷐᦛ✢ߣᝒ߃ࠇ߫‫ߘޔ‬ߩ㔛ⷐᦛ✢߆ࠄዉ߆ࠇࠆഭ௛㊂ߪߔߴߡห⾰ߥ߽ߩߢߥߌࠇ߫ߥࠄߥ޿‫ᦨޕ‬ૐ⾓㊄ߩᢥ⣂ߢ⠨߃ࠆߥࠄ߫‫ޔ‬ዋߥߊߣ߽ᦨૐ⾓㊄ߩ਄᣹ߦࠃߞߡ⋥ធ⊛ߥᓇ㗀ࠍⵍࠆഭ௛⠪ߦ‫ޔ‬ኻ⽎ࠍ⛉ࠆᔅⷐ߇޽ࠆ‫ޕ‬ᱷᔨߥ߇ࠄ‫♽ᤨޔ‬೉ಽᨆߢߪ㓸⚂ߐࠇߚ࠺࡯࠲‫ߩੱ৻ࠅ߹ߟޔ‬୘ੱࠍㅊ〔⺞ᩏߒߡ޿ߥ޿
࠺࡯࠲ࠍ↪޿ࠆߚ߼ߦ‫ᦨޔ‬ૐ⾓㊄਄᣹ߦࠃߞߡᓇ㗀ࠍฃߌߚഭ௛⠪߇‫ߩߘޔ‬ᓟߤ߁ߥߞߚ߆
ࠍ⍮ࠆߎߣߪߢ߈ߥ޿‫ޔߦ߃ࠁޕ‬ઍℂᜰᮡߣߒߡ 10 ઍߩ㓹↪㊂ࠍ↪޿ࠆߒ߆ߥ޿ߩߢ޽ࠆ‫ޕ‬⏕߆ߦ‫☨ޔ‬࿖ߦ߅޿ߡ 10 ઍߩ㓹↪⠪ߩᄙߊ߇ᦨૐ⾓㊄㗵ㄭㄝߩ⡯ߦዞ޿ߡ޿ࠆ‫ޔ߃޿ߪߣޕ‬ߘߩᢙߪඨᢙߦߒ߆ḩߚߥ޿‫ᦨޔߦ߁ࠃߩߎޕ‬ૐ⾓㊄ߩᓇ㗀ࠍฃߌߥ޿ഭ௛⠪߹ߢ߇ផ⸘ߦ
㧙㧙฽߹ࠇߡߒ߹߁ߚ߼‫ޔ‬ㆡಾߥଏ⛎஥ߩⷐ࿃ࠍផ⸘ᑼߦ฽߼ߡ‫ߩߘޔ‬Ⴧᷫ߇㓹↪㊂ߦਈ߃ࠆᓇ
㗀ࠍࠦࡦ࠻ࡠ࡯࡞ߔࠆᔅⷐ߇޽ࠆ‫ౕޕ‬૕⊛ߦߤߩࠃ߁ߥଏ⛎஥ߩⷐ࿃߇‫ޔ‬ផ⸘ᑼߦ฽߹ࠇߡ
޿ࠆ߆ߣ޿߃߫‫ޔ‬10 ઍߩోੱญߦභ߼ࠆഀว (Wachter and Kim (1979), Brown et al.
(1983), Wellington (1991)) ‫ ޔ‬ァ 㓌 ߳ ߩ ട ౉ ഀ ว (Mincer (1975), Brown et al. (1983),
Wellington (1991)) ߣ޿ߞߚ߽ߩ߇ណ↪ߐࠇߡ޿ࠆ‫ޔߚ߹ޕ‬᭎ᔨ਄‫ޔ‬E ߪ㓹↪⠪ᢙࠍߣࠆߴ
߈ߢ޽ࠆ߇‫ޔ‬㓹↪⠪㧙ੱญᲧ₸߇ណ↪ߐࠇߡ޿ࠆ‫ੱޔ߽ߢߎߎޕ‬ญߣ޿߁ഭ௛ଏ⛎஥ߩⷐ࿃ߢ‫ޔ‬ផ⸘ࠍࠦࡦ࠻ࡠ࡯࡞ߒߡ޿ࠆߎߣߦߥࠆ‫ޕ‬ߜߥߺߦ‫ޔ‬ታ⸽⎇ⓥߩᄙߊߪ㓹↪㊂ߩേ߈ߦ⌕⋡ࠍߒߡ޿ࠆ‫ߢ࡞࠺ࡕޕ‬㔛ⷐ೙⚂ࠍ઒ቯߒߡ޿ࠆߚ߼‫⋥߇ࠇߘޔ‬ᗵ⊛ߛ߆ࠄߢ޽ࠆ‫ᦨޔߒ߆ߒޕ‬ૐ⾓㊄߇ഭ௛Ꮢ႐ߦਈ߃ࠆᓇ㗀ࠍ⠨߃ࠆߥࠄ߫‫ޔ‬ᄬᬺ₸ࠍⵍ⺑᣿ᄌᢙߣߒߚᣇ⒟ᑼࠍ‫ࠄ߆࡞࠺ࡕޔ‬ዉ಴ߔࠆߎߣ߽ઍᦧ᩺ߣߒߡ⠨߃ࠄࠇࠆ‫ޔߛߚޕ‬ᄬᬺ₸ࠍᜰᮡߦ↪޿ߚ⺰ᢥߪ‫ߤ߶ߐޔ‬ᄙߊߥ޿‫ޕ‬Brown et al. (1982) ߪ‫ޔ‬ᄬᬺ₸߇޽߹ࠅ↪޿ࠄࠇߥ޿ℂ↱ߣߒߡ‫ޔ‬1)᳞⡯ࠍ޽߈ࠄ߼ࠆ‫ޔߪ޿ࠆ޽ޔ‬ㅒߦ㕖ഭ௛ജ߆ࠄᄬᬺ⠪ߦߥࠆ୘ੱ߇޿ࠆߚ߼‫ޔ‬ᄬᬺ₸ߦࠃߞߡዞᬺᯏળߩ೙㒢ࠍᝒ߃ࠆߎߣߪㆡಾߢߥ޿‫ޕ‬2)ᄬᬺ⠪ᢙ‫⥄ࠅ߹ߟޔ‬ಽ߇ᄬᬺ⠪ߢ޽ࠆ߆㕖ഭ௛ജߩ⁁ᘒߢ޽ࠆ߆ߪ୘ੱߩ್ᢿߦଐሽߒߡ
޿ࠆ‫ޕ‬3)㓹↪ߦὶὐࠍᒰߡࠇ߫‫ࡓࠗ࠲࡞ࡈޔ‬ഭ௛߆ࠄࡄ࡯࠻࠲ࠗࡓഭ௛߳ߩᄌൻ‫ࠅ߹ߟޔ‬ዞᬺᒻᘒߩᄌൻߦ߽⌕⋡ߢ߈ࠆ‫ߚߞ޿ߣޔ‬ὐࠍ޽ߍߡ޿ࠆ‫ޕ‬ᰴߦ‫ᦨޔ‬ૐ⾓㊄ߩᜰᮡ MW ߦߟ޿ߡ⹦ߒߊ⷗ߡ޿ߎ߁‫ޕ‬ㅢᏱ‫ޔ‬MW ߦߪࠞࠗ࠷࡮ࠗࡦ࠺
࠶ࠢࠬ (Kaitz Index) ߣ๭߫ࠇࠆᜰᮡ߇↪޿ࠄࠇࠆ‫ᦨޔߪߣࠬࠢ࠶࠺ࡦࠗ࡮࠷ࠗࠞޕ‬ૐ⾓㊄ߣฦ↥ᬺߦ߅ߌࠆᐔဋ⾓㊄ߩᲧ₸ࠍ৻ߟߦ߹ߣ߼ߚ߽ߩߢ޽ࠅ‫↥ޔ‬ᬺߏߣߦᦨ⾓ߩㆡ↪₸ߢ㊀ߺࠍߟߌߡ޿ࠆ‫ޕ‬ၮᧄ⊛ߥࠞࠗ࠷࡮ࠗࡦ࠺࠶ࠢࠬߪ
MWt = Ǜi ( mt / wit) cit.i(8),ߣቯ⟵ߐࠇߡ޿ࠆ‫ ߢߎߎޕ‬mt ߪ t ᦼߩᦨૐ⾓㊄㗵‫ޔ‬wit ߪ t ᦼߦ߅ߌࠆ i ↥ᬺߩᐔဋ⾓㊄㗵‫ޔ‬㨏ߪߘߩ↥ᬺߦ߅ߌࠆᦨૐ⾓㊄ߩㆡ↪₸ࠍ␜ߔ‫ޔߚ߹ޕ‬႐วߦࠃߞߡಽᨆߩኻ⽎ߣߔࠆഭ௛
⠪ߩഀว‫ో߫߃଀ޔ‬ഭ௛⠪ߦභ߼ࠆ 10 ઍߩ㓹↪⠪ߩഀว╬ࠍਸ਼ߓࠆ‫☨ޕ‬࿖ߢߪ‫ޔ‬ᐕߏߣߦᦨૐ⾓㊄߇ㆡ↪ߐࠇࠆ↥ᬺ‫ޔ‬⡯⒳߇㒢ࠄࠇ‫▸ߩߘޔ‬࿐߽ᄌൻߒߡ޿ࠆ‫ᦨޔߦ߃ࠁޕ‬ૐ⾓㊄㗵ߘߩ߽ߩࠍ૶߁ߣ‫ޔ‬ଥᢙࠍ⛘ኻ୯ߢㆊᄢផቯߒߡߒ߹߁‫ߩߘޕ‬ᓇ㗀ࠍട๧ߔࠆߚ߼ߦ‫ߩߎޔ‬ࠞࠗ࠷࡮ࠗࡦ࠺࠶ࠢࠬ߇↪޿ࠄࠇߡ޿ࠆ‫☨ޔߚ߹ޕ‬࿖ߢߪ 1970 ᐕઍඨ߫߹ߢߩ‫ޔ‬10 ઍߩ⾓㊄࠺࡯࠲ߪᓧࠆߎߣ߇ߢ߈ߥ߆ߞߚ‫࠲࡯࠺ߩߎޕ‬਄ߩ೙⚂߽ࠞࠗ࠷࡮ࠗࡦ࠺࠶ࠢࠬࠍઍℂᜰᮡߣߒߡ↪޿ߥߌࠇ߫ߥࠄߥ߆ߞߚᄢ߈ߥⷐ࿃ߢ޽ࠆߣ޿߁ (Card and Krueger, 1995)‫ޕ‬ߐࠄߦ‫ߚ޿↪ࠍࠬࠢ࠶࠺ࡦࠗ࡮࠷ࠗࠞޔ‬ቯᑼൻߪ‫ᦨޔ‬ૐ⾓㊄ߩᓇ㗀ࠍฃߌࠆഭ௛⠪ߣ৻⥸ഭ௛⠪ߣߩઍᦧࠍ‫ࠆ޽ޔ‬⒟ᐲ‫ޔ‬⠨ᘦߒߚߎߣߦߥࠆ‫(ޕ‬8)ᑼߩ w ߦߪ‫ᦨޔ‬ૐ⾓㊄ߩታ⾰ൻߣ޿߁ᓎഀ߽޽ࠆ߇‫ᦨޔ‬ૐ⾓㊄਄᣹ߩᓇ㗀ࠍฃߌߥ޿৻⥸ഭ௛⠪ߩ⾓㊄߽⴫ߒߡ޿ࠆ‫ޔࠅ߹ߟޕ‬m ߣ w ߩഭ௛ࠦࠬ࠻ࠍᜬߟ‫ޔ‬ઍᦧ⊛ߥੑ࠲ࠗࡊߩഭ௛⠪߇↢↥ⷐ⚛ߣߒߡᗐቯߐࠇߡ޿ࠆ‫ޕ‬ߚߛߒ‫ޔ‬w ߩ⾓㊄ߢ௛ߊഭ௛⠪ᢙ߇(8)ᑼߦߪ᣿␜ߐࠇߡ޿ߥ޿ߩߢ‫ߪߡߒߣ࡞࠺ࡕޔ‬ਇቢోߥ߽ߩߢ޽ࠆ‫ޕ‬㧙㧙ߎߩࠃ߁ߦ(7)ᑼߪ‫ޔ‬ㅢᏱߩ㔛ⷐᦛ✢ߣߪ⇣ߥࠆߚ߼ߦ‫ޔ‬Ǫ߆ࠄዉ߆ࠇࠆᒢജᕈ߽ㅢᏱߩ㔛ⷐᒢജᕈߣߪ⇣ߥࠆ‫ࠅ➅ޕ‬㄰ߒߦߥࠆ߇‫ޔ‬㔛ⷐ㑐ᢙ߆ࠄዉ߆ࠇࠆഭ௛㊂ߪߔߴߡ‫ޔ‬ห৻ߩ⾓㊄ࠍᓧߡ޿ࠆห⾰ߩഭ௛⠪ߢ޽ࠆߣᗐቯߐࠇߡ޿ࠆ‫⺑ⵍޔߒ߆ߒޕ‬᣿ᄌᢙߩ E ߪ㓹↪⠪㧙ੱญᲧ₸ࠍߣߞߡ޿ࠆߚ߼‫ᦨޔ‬ૐ⾓㊄ߩᓇ㗀ࠍ⋥ធߪฃߌߥ޿㓹↪⠪߽ߘߎߦߪ฽߹ࠇࠆ‫ߐޕ‬ࠄߦ෩ኒߦ޿߃߫‫ޔ‬ฦഭ௛⠪‫⾓ߌࠊࠅߣޔ‬㊄ᡷᱜએ೨ߦᓧߡ޿ߚ⾓㊄ߦࠃߞߡ‫ޔ‬ᡷᱜ೨ᓟߩ
⾓㊄਄᣹᏷߽⇣ߥࠆ‫⾓ޔߪߣߎߩߎޕ‬㊄ߩᄌൻ₸ࠍㆊᄢߦ‫ޔ‬㓹↪ߩᄌൻ₸߇ㆊዊߦ⷗Ⓧ߽ߞߡ޿ࠆߎߣߦߥࠆ‫ޔࠅ߹ߟޕ‬Ǫߪᦨૐ⾓㊄߇⋥ធ㓹↪ߦਈ߃ࠆᓇ㗀ࠍ‫⛘ޔ‬ኻ୯ߢ⹏ଔߒߡㆊ
ዊߦផ⸘ߒߡ޿ࠆ‫ᦨޕ‬ૐ⾓㊄ߩሽ࿷߇‫ޔ‬ૐ⾓㊄ഭ௛⠪ߩዞᬺᯏળࠍ೙⚂ߒߡ޿ࠆߣ޿߁᡽╷⊛ߥࠗࡦࡊ࡝ࠤ࡯࡚ࠪࡦࠍ⠨߃ࠆ႐ว‫ߪߣߎߩߎޔ‬⠨ᘦߦ౉ࠇߡ߅ߊᔅⷐ߇޽ࠆ‫ޔߦߺߥߜޕ‬Brown (1999) ߪ Neumark and Wascher (1997) ߩ࠺࡯࠲ࠍ↪޿ߡ⧯ᐕጀ㧔16㧙24 ᱦ㧕ࠍ‫ޔ‬
Card and Krueger (1995) ߩ࠺࡯࠲ࠍ↪޿ߡ 10 ઍ㧔16㧙19 ᱦ㧕ߩᒢജᕈߩ୯ࠍߘࠇߙࠇ⵬
ᱜߒߡ޿ࠆ‫⧯ޔߪࠇߘޕ‬ᐕጀߢ 9.2 ୚‫ޔ‬10 ઍߢߪ 5 ୚ᒙߣ‫(ޔ‬7)ᑼ߆ࠄᓧࠄࠇࠆផ⸘୯ࠃࠅ
߽ᄢ߈޿߽ߩߢ޽ࠆ‫ޕ‬ࠗ ਥⷐߥታ⸽⚿ᨐ
Brown et al. (1982, 1983) ߪᦨૐ⾓㊄߇㓹↪ߦߤߩࠃ߁ߥലᨐࠍ෸߷ߔ߆ࠍᢛℂ‫ޔ‬ᬌ⸽ߒߚ‫♽ᤨޔ‬೉ಽᨆߩ㓸ᄢᚑߣ޿߃ࠆ⺰ᢥߢ޽ࠆ‫ߩߎߦ߃ࠁޕ‬ੑߟߩ⺰ᢥߪ‫ᦨޔ‬ૐ⾓㊄߇⼏⺰ߐࠇࠆ㓙ߦ‫ޔ‬ᄢ߈ߥᓇ㗀ജࠍᜬߜߟߠߌߡ޿ߚ‫ޕ‬Brown et al. (1982) ߪ‫ᦨޔ‬ૐ⾓㊄ߦ㑐ߔࠆㆊ
෰ 25 ᧄߩ⺰ᢥߩታ⸽⚿ᨐࠍ߹ߣ߼‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦਈ߃ࠆᓇ㗀ࠍᢛℂߒߚ߽ߩߢ޽ࠆ‫ޕ‬
Brown et al. (1982) ߢขࠅᛒࠊࠇߡ޿ࠆฦ⺰ᢥߩ࠺࡯࠲࡮ࠨࡦࡊ࡞ᦼ㑆ߪ‫ޔ‬1950 ᐕઍ߆ࠄ1960 ᐕઍ߹ߢ‫ ߪ޿ࠆ޽ޔ‬1970 ᐕઍೋ㗡߹ߢߦ߆ߌߡߢ޽ࠆ‫ߪߢߎߘޕ‬ฦ⺰ᢥߦ߅ߌࠆ࠺࡯
࠲ߩᢛวᕈࠍ࿑ࠅ‫ޟޔ‬10㧑ߩᦨૐ⾓㊄ߩ਄᣹ߪ‫ޔ‬1 ߆ࠄ 3㧑ߩ᏷ߢ 10 ઍߩ㓹↪㊂ࠍᷫዋߐߖ
ࠆ‫ࠍ⺰⚿߁޿ߣޠ‬ዉ޿ߡ޿ࠆ‫ޕ‬઒ߦ‫ޔ‬10 ઍߩ߁ߜඨಽ߇㓹↪ߐࠇߡ޿ࠆߣߔࠇ߫‫ޔ‬㓹↪㧙ੱญᲧ₸ߩᷫዋߪ 0.5 ߆ࠄ 1.5㧑ߣ޿߁ߎߣߦߥࠆ‫ᦨޔߚ߹ޕ‬ૐ⾓㊄߇ᄬᬺ₸ߦਈ߃ࠆᓇ㗀ߪ‫ޔ‬㓹↪㊂ࠃࠅ߽߿߿᏷߇ᐢߊ‫ޟ‬10㧑ߩ਄᣹߇‫ޔ‬0 ߆ࠄ 3㧑ࡐࠗࡦ࠻߶ߤᄬᬺ₸ࠍჇടߐߖࠆ‫ޠ‬ߣߒߡ޿ࠆ‫ޕ‬ߎߩ⚿ᨐࠍ〯߹߃ߡ‫ޔ‬Brown et al. (1983) ߢߪ 1979 ᐕ߹ߢ࠺࡯࠲ࠍᦝᣂߒ‫ߦࠄߐޔ‬ᑼߩ․ቯൻࠍᄙᢙ⹜ߺߡ޿ࠆ‫ޟޔߪߢߎߎޕ‬10㧑ߩᦨૐ⾓㊄ߩ਄᣹ߪ‫ޔ‬10 ઍߩ㓹↪ࠍ 1㧑ᷫዋߐߖࠆ‫ޔߣޠ‬ㆊ෰ߩታ⸽⚿ᨐ߆ࠄᓧࠄࠇߚ୯ߩਅ㒢߇ᓧࠄࠇߡ޿ࠆ‫ߚ߹ޕ‬ᄬᬺ₸ߦኻߒߡߪ‫ޔ‬
ᦨૐ⾓㊄ߪ᦭ᗧߥᓇ㗀ࠍਈ߃ߡ߅ࠄߕ‫߽ࠄߜߎޔ‬ਅ㒢୯ߢ޽ࠆ‫ ߦࠄߐޕ‬Solon (1985) ߩផ⸘ߪ‫ޔ‬Brown ࠄߩផቯ୯ࠃࠅ߽‫ࠅ߆߫߆ߕࠊޔ‬ૐ޿୯ࠍ␜ߒߡ޿ࠆ‫ޕ‬Solon ߪ‫ޔ‬Brown et al.
(1983) ߩផ⸘ߦ↢ߓߡ޿ߚቄ▵ᕈߩ໧㗴ࠍୃᱜߒߚ߽ߩߢ޽ࠆ‫ޕ‬ቄ▵ᕈߩᘕ㊀ߥขࠅᛒ޿߇
ᔅⷐߦߥࠆߎߣߪ‫ ߜࠊߥߔޔ‬10 ઍߩ㓹↪㊂ߩᄌൻ߇ᭂ߼ߡቄ▵⊛ߥ߽ߩߢ޽ࠆߎߣࠍᗧ๧

㧙㧙ߒߡ޿ࠆ 3‫ޕ‬Solon ߩផ⸘୯ߪ Brown ࠄߩផ⸘ߦᲧߴߡ t ୯߽਄᣹ߒߡ߅ࠅ‫ࠅࠃޔ‬቟ቯ⊛ߥ⚿ᨐߢ޽ࠆ‫ޕ‬
Brown et al. (1982 1983) ߆ࠄᓧࠄࠇߚ‫ߩઁߩߘޔ‬⍮⷗ࠍ೉᜼ߔࠆߣ‫ޔ‬એਅߩࠃ߁ߥ߽ߩ
߇޽ࠆ‫ޕ‬1)‫ޔ‬㤥ੱ޽ࠆ޿ߪᅚᕈߪ‫ޔ‬ㅢᏱ‫ᦨޔ‬ૐ⾓㊄਄᣹ߩᓇ㗀ࠍฃߌ߿ߔ޿ߪߕߢ޽ࠆ‫ߒޕ‬߆ߒታ⸽⎇ⓥ߆ࠄߪੱ⒳‫ޔ‬ᕈ೎ߩᏅ⇣ߦࠃߞߡᓇ㗀ߦ⏕࿕ߣߒߚ㆑޿ߪ⷗ࠄࠇߡ޿ߥ޿‫ޕ‬
2)‫ᦨޔ‬ૐ⾓㊄ߩᜰᮡࠍ‫⾓ޔ‬㊄᳓Ḱߣࠞࡃ࡟࠶ࠫߦಽߌߡߘߩലᨐࠍߺࠆߣ‫⾓ޔ‬㊄᳓Ḱߩ߶߁߇㓹↪ߦኻߒߡᒝ޿ᓇ㗀ࠍ෸߷ߒߡ޿ࠆ‫ޕ‬3)‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߦࠃߞߡ‫ޔ‬10 ઍߩ㓹↪ߦභ߼ࠆࡄ࡯࠻࠲ࠗࡑ࡯ߩᲧ₸߇㜞߹ࠆ‫ޕ‬4)‫ޔ‬10 ઍ㧔16㧙19㧕ߣߪ⇣ߥࠅ‫ޔ‬20㧙24 ᱦߩ㓹↪㊂ߦ
ᦨૐ⾓㊄߇ਈ߃ࠆᓇ㗀ߪ߆ߥࠅዊߐ޿‫ ߪࠇߎޕ‬20 ઍ೨ඨߩ㓹↪⠪ߢᦨૐ⾓㊄㗵ߩ⛎ᢱߢ௛޿ߡ޿ࠆੱߪ‫ోޔ‬૕ߩ 15㧑ߦߒ߆ㆊ߉ߥ޿ߚ߼ߢ޽ࠆ‫ޕ‬ㅒߦᦨૐ⾓㊄ߩ਄᣹ߪᄬᬺ₸ߦᓇ㗀ࠍਈ߃ߡ޿ࠆ‫ᦨޕ‬ૐ⾓㊄ 10㧑ߩ਄᣹ߪ 0.2㧑߶ߤᄬᬺ₸ࠍ᛼ߒ਄ߍࠆ‫ޕ‬⴫㧞㧙㧝 ᤨ♽೉ಽᨆߩਥⷐ⚿ᨐ ߘߩ 
㩷㩷
䊂䊷䉺㩷
ᦼ㑆㩷
ⵍ⺑᣿ᄌᢙ㩷
ᦨૐ⾓㊄䈱㩷
ᜰᮡ㩷ઁ䈱⺑᣿ᄌᢙ㩷ਥ䈭⚿ᨐ㩷㪙㫉㫆㫎㫅㩷㪼㫋㩷㪸㫃㪅㩷㩿㪈㪐㪏㪉㪀㩷㪈㪐㪎㪇䋭㪈㪐㪏㪈 㑆䈮⊒⴫䈘䉏䈢 㪉㪌 ᧄ䈱⺰ᢥ䈱ᢛℂ㪈㪐㪌㪋 ᐕ䈎䉌 㪈㪐㪍㪇 ᐕઍ㩷䈅䉎䈇䈲 㪎㪇 ᐕઍೋ㗡䉁䈪㩷㩷㪙㫉㫆㫎㫅㩷㪼㫋㩷㪸㫃㪅㩷㩿㪈㪐㪏㪊㪀㩷㪪㫆㫃㫆㫅㩷㩿㪈㪐㪏㪌㪀㩷

㪚㪧㪪㪁㩷

㪚㪧㪪㪁㩷

㪈㪐㪌㪋㩷㪠㩷㵨㩷㪈㪐㪎㪐㩷㪠㪭㩷 㩷㪈㪐㪌㪋㩷㪠㩷㵨㩷㪈㪐㪎㪐㩷㪠㪭㩷 㩷㓹↪⠪䋭ੱญᲧ₸㩷㓹↪⠪䋭ੱญᲧ₸㩷㩷䉦䉟䉿䊶䉟䊮䊂䉾䉪䉴㩷䉦䉟䉿䊶䉟䊮䊂䉾䉪䉴㩷ቄ▵䉻䊚䊷㩷
䉺䉟䊛䊶䊃䊧䊮䊄㩷ᄬᬺ₸㩷㩷ోੱญ䈮භ䉄䉎㩷㪈㪇 ઍ䈱ੱญഀว㩷䈠䈱ઁଏ⛎஥䈱ⷐ࿃ 㪈㩷㪈㪇䋦䈱ᦨ ⾓ ਄ ᣹ 䈲䇮㪈㪇 㪈㪇䋦䈱ᦨ ⾓ ਄ ᣹ 䈲䇮㪈㪇ઍ䈱㓹↪㊂䉕 㪈 䈎䉌 㪊䋦 ઍ䈱㓹↪㊂䉕 㪈䋦ᒝᷫᷫዋ䈘䈞䉎䇯㩷
ዋ䈘䈞䉎䇯㩷
㩷㩷ᄬᬺ₸䉕 㪇 䈎䉌 㪊䋦䈱▸ ᄬᬺ ₸䈮䈲ᓇ㗀䉕ਈ䈋࿐䈪਄᣹䈘䈞䉎䇯㩷䈭䈇䇯㩷㩷㩷ቄ▵䉻䊚䊷㩷 㬍㩷 䉺䉟䊛䊶䊃䊧䊮䊄㩿㪉 ਸ਼㗄䉅㪀㩷ᄬᬺ₸㩷ోੱญ䈮භ䉄䉎㩷㪈㪇 ઍ䈱ੱญഀว㩷䈠䈱ઁଏ⛎஥䈱ⷐ࿃ 㪈㩷㪙㫉㫆㫎㫅㩷 㪼㫋㩷 㪸㫃㪅㩷 㩿㪈㪐㪏㪊㪀㩷 䈱ୃᱜ 㩷㩷㪈㪇䋦䈱ᦨ⾓਄᣹䈲 㪈㪇 ઍ䈱㓹↪㊂䉕⚂ 㪈䋦ᷫዋ䈘䈞䉎䇯㩷㩷

16㧙19 ᱦߩੱญߦභ߼ࠆ 16㧙17 ᱦߩഀว‫ޕ‬16㧙19 ᱦੱญߦභ߼ࠆァ㓌ട౉⠪ߩഀว‫ޕ‬ㅪ㇌᡽ᐭߩ㓹↪‫⸠ޔ‬✵ࡊࡠࠣ࡜ࡓ߳ߩᡰ಴ഀว㧔10 ઍߩੱญߢ⺞ᢛ㧕‫ޕ‬* Current Population Survey: ☨࠮ࡦࠨࠬዪߣഭ௛ዪ߇วหߢ⺞ᩏࠍⴕߞߡ޿ࠆᣣᧄߩ‫ޡ‬ഭ௛ജ⺞ᩏ‫⹥ߦޢ‬ᒰߔࠆ⺞ᩏ
1

ߎߩ Brown et al. (1982, 1983) ߩࠗࡦࡊ࡝ࠤ࡯࡚ࠪࡦ߇‫ޔ‬80 ᐕઍࠍㅢߒߡᓇ㗀ജࠍᜬߜߟߠߌߡ߈ߚℂ↱ߣߒߡ‫ޔ‬ᓐࠄߩ⺰ᢥએ㒠‫ᦨޔ‬ૐ⾓㊄ߦ㑐ߔࠆ⺰ᢥᢙ߇ᷫዋߒߚߎߣ߽޽ࠆ‫ޕ‬

3଀߃߫‫ޔ‬Card and Krueger (1995) ߩ Figure6.4 ࠍෳᾖ‫ޕ‬㧙㧙

80 ᐕઍߩඨ߫એ㒠ߪ‫ޔ‬ㅪ㇌ᦨૐ⾓㊄ߩᒁ߈਄ߍ߇ⴕࠊࠇߥ߆ߞߚߚ߼‫ޔ‬ቇ໧⊛ߦߪᦨૐ⾓㊄ߦኻߒߡ‫ޔ‬એ೨߶ߤ㑐ᔃ߇ะߌࠄࠇߥߊߥߞߡ޿ߚߩߢ޽ࠆ‫ᦨޔࠄ߇ߥߒ߆ߒޕ‬ૐ⾓㊄ߩ㗵⥄૕ߪᝪ߃⟎߆ࠇߡ޿ߚ߽ߩߩ‫‛ߪᦼᤨߩߎޔ‬ଔ߇਄᣹ߒߡ޿ߚ‫ޔ߃ࠁࠇߘޕ‬ታ⾰ߩᦨૐ⾓㊄㗵ߪਅ⪭ߒߡ޿ߚ‫‛ޔߚ߹ޕ‬ଔߩ਄᣹ߦ઻޿ഭ௛⠪ߩᐔဋ⾓㊄㗵߽਄᣹ߒߡ޿ߚߩߢ‫ᦨޔ‬
ૐ⾓㊄ߩᜰᮡߢ޽ࠆࠞࠗ࠷࡮ࠗࡦ࠺࠶߽ࠢࠬẋᰴ‫ޔ‬ૐਅߒߡ޿ߚߎߣߦߥࠆ‫ޕ‬⴫㧞㧙㧞 ᤨ♽೉ಽᨆߩਥⷐ⚿ᨐ ߘߩ 㩷㩷㪮㪼㫃㫃㫀㫅㪾㫋㫆㫅㩷㩿㪈㪐㪐㪈㪀㩷㪚㪸㫉㪻㩷㪸㫅㪻㩷㪢㫉㫌㪼㪾㪼㫉㩷㩿㪈㪐㪐㪌㪀㩷

䊂䊷䉺㩷

㪚㪧㪪㩷

㪚㪧㪪㩷

ᦼ㑆㩷

㪈㪐㪌㪋㩷㪠㩷㵨㩷㪈㪐㪏㪍㩷㪠㪭㩷㪈㪐㪌㪋㩷㪠㩷㵨㩷㪈㪐㪐㪊㩷㪠㪭㩷 㩷ⵍ⺑᣿ᄌᢙ㩷

㓹↪⠪䋭ੱญᲧ₸㩷㓹↪⠪䋭ੱญᲧ₸㩷

ᦨૐ⾓㊄䈱ᜰᮡ㩷 䉦䉟䉿䊶䉟䊮䊂䉾䉪䉴㩷䉦䉟䉿䊶䉟䊮䊂䉾䉪䉴㩷ઁ䈱⺑᣿ᄌᢙ㩷ቄ▵䉻䊚䊷㩷 㬍㩷 䉺䉟䊛䊶䊃䊧䊮䊄㩷㩿㪉 ਸ਼㗄䉅฽䉃㪀㩷ᄬᬺ₸㩷ోੱญ䈮භ䉄䉎 㪈㪇 ઍ䈱㩷ੱญഀว㩷䈠䈱ઁଏ⛎஥䈱ⷐ࿃ 㪈㩷ቄ▵䉻䊚䊷㩷 㬍㩷 䉺䉟䊛䊶䊃䊧䊮䊄㩷㩿㪉 ਸ਼㗄䉅฽䉃㪀㩷ᄬᬺ₸㩷ోੱญ䈮භ䉄䉎 㪈㪇 ઍ䈱㩷ੱญഀว㩷䈠䈱ઁଏ⛎஥䈱ⷐ࿃ 㪈㩷ਥ䈭⚿ᨐ㩷㪈㪇䋦䈱ᦨ⾓਄᣹䈲䇮㪈㪇 ઍ䈱㓹↪㊂䉕
㪇㪅㪍䋦೨ᓟ䇮ᷫዋ䈘䈞䉎䇯㩷㪉㪇 ઍ೨ඨ䈱㓹↪㊂䈮䈲ᓇ㗀䉕ਈ䈋䈭䈇㩷㪮㪼㫃㫃㫀㫅㪾㫋㫆㫅㩷 㩿㪈㪐㪐㪈㪀㩷 䈱䊂䊷䉺䉕ᦝᣂ䈚䈢䉅䈱㩷㪈㪇䋦䈱ᦨ⾓਄᣹䈲 㪈㪇 ઍ䈱㓹↪㊂䉕
㪇㪅㪎䋦೨ᓟ䇮ᷫዋ䈘䈞䉎䇯㩷1

16㧙19 ᱦߩੱญߦභ߼ࠆ 16㧙17 ᱦߩഀว‫ޕ‬16㧙19 ᱦੱญߦභ߼ࠆァ㓌ട౉⠪ߩഀว‫ޕ‬ㅪ㇌᡽ᐭߩ㓹↪‫ޔ‬⸠✵ࡊࡠࠣ࡜ࡓ߳ߩᡰ಴ഀว㧔10 ઍߩੱญߢ⺞ᢛ㧕‫ޕ‬

ᦨૐ⾓㊄㗵ߩᐔဋ⾓㊄㗵ߦኻߔࠆ⋧ኻ⊛ߥਅ⪭ࠍ೑↪ߒߡ‫ޔ‬1980 ᐕઍߩ࠺࡯࠲ࠍᦝᣂߒߚ
߽ߩ߇ Wellington (1991) ߢ޽ࠆ‫ޕ‬Wellington ߩಽᨆ߽‫ޔߚ߹ޔ‬Brown et al. (1983) ߩᚻᴺࠍ〯ⷅߒߚ߽ߩߢ޽ࠆ‫ᦨޔߪࡦ࡚ࠪ࡯ࠤ࡝ࡊࡦࠗޕ‬ૐ⾓㊄ߩ਄᣹ߪ㓹↪㊂ࠍᷫࠄߔᣇะߦ
௛ߊߣ޿߁ὐߢ৻⥌ߒߡ޿ࠆ‫ߩߘޔߒߛߚޕ‬ᓇ㗀ജߪ⋧ኻ⊛ߦᒙߊߥߞߡ߅ࠅ‫ޔ‬10㧑ߩᦨૐ
⾓㊄਄᣹ߪ 0.6㧑೨ᓟ 10 ઍߩ㓹↪㊂ࠍᷫዋߐߖࠆߣ޿߁߽ߩߢ޽ࠆ‫ޔߚ߹ޕ‬20 ઍ೨ඨ㧔20
㧙24㧕ߩ㓹↪ߦኻߒߡߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߪᓇ㗀ࠍਈ߃ߡ޿ߥ޿⚿ᨐ߇ᓧࠄࠇߡ޿ࠆ‫ࠄߐޕ‬ߦಽᨆߩᦼ㑆ࠍᑧ߫ߒߚ Card and Krueger (1995) ߩ⚿ᨐ߽‫⧯ޔ‬ᐓ Wellington ߩ୯ࠃࠅᄢ
߈ߊߥࠆ߽ߩߩ‫ޔ‬㧙0.7㧑ߣ 1970 ᐕઍ߹ߢߩ࠺࡯࠲ࠍ↪޿ߚ⚿ᨐߦᲧߴࠆߣ‫ޔ‬ଐὼዊߐߥ୯
ࠍ␜ߒߡ޿ࠆ‫ޕ‬80 ᐕઍߩ࠺࡯࠲ࠍᦝᣂߒߚߎߣߢ㓹↪㊂ߩᷫዋ߇✭๺ߐࠇߚℂ↱ߦߟ޿ߡ‫ޔ‬Hamermesh(1993) ߪᦨૐ⾓㊄ߩଔ୯߇⋧ኻ⊛ߦਅ߇ࠅ‫ోޔ‬૕ߩ⾓㊄ಽᏓߦਈ߃ࠆᓇ㗀ജ߇ᒙ߹ߞߚߎߣ
ࠍ޽ߍߡ޿ࠆ‫ᦨޔࠄ߇ߥߒ߆ߒޕ‬ૐ⾓㊄㗵ߩㄭㄝߢ௛ߊ 10 ઍߩഭ௛⠪ߩഀวߪ‫ోޔ‬૕ߩ 25㧑
߆ࠄ 30㧑ߩ㑆ߣ 1970 ᐕઍߣ 1980 ᐕઍߢߐ߶ߤᄌൻߪߒߡ޿ߥ޿ (Brown (1999))‫ޔߚ߹ޕ‬ᦨૐ⾓㊄ࠍㆡ↪ߒߡ޿ࠆ↥ᬺߩ▸࿐߽᜛ᄢߒߡ޿ࠆߩߢ‫⥄ࠬࠢ࠶࠺ࡦࠗ࡮࠷ࠗࠞޔ‬૕ߪ਄᣹ߒߡ޿ࠆ‫(ޕ‬7)ᑼߩଥᢙߩૐਅߪ‫ޔ‬නߦ‫ᦨޔ‬ૐ⾓㊄ߩଔ୯ਅ⪭ߛߌ߇‫ޔ‬ේ࿃ߣߪ⸒߃ߥ޿ࠃ߁
㧙㧙ߢ޽ࠆ‫ޕ‬ ࡄࡀ࡞࡮࠺࡯࠲ߦࠃࠆಽᨆ
ࠕ ᭎ⷐ
1990 ᐕઍߦ౉ࠅㅪ㇌ᦨૐ⾓㊄㗵߇ᡷᱜߐࠇᆎ߼ߚߚ߼ߦ‫ޔ‬90 ᐕઍߪᦨૐ⾓㊄߇⚻ᷣቇߩಽᨆኻ⽎ߣߒߡ‫ޔ‬ౣ߮⣉శࠍᶎ߮ࠆࠃ߁ߦߥࠆ‫ޔߚ߹ޕ‬80 ᐕઍ߹ߢߩᤨ♽೉ಽᨆਛᔃߣߪ⇣ߥࠅ‫ޔ‬90 ᐕઍߩ⺰ᢥߪࡄࡀ࡞࡮࠺࡯࠲ߩ૶↪߇ਛᔃߣߥߞߡ޿ࠆ‫ޕ‬ഭ௛⚻ᷣಽᨆߩ᭽‫ߥޘ‬႐㕙ߢߪ‫ޔ‬㓸⸘࠺࡯࠲ࠃࠅࡄࡀ࡞࡮࠺࡯࠲ߩ૶↪߇ᅢ߹ߒ޿ߣߐࠇߡ޿ࠆ‫ޔߕࠄࠊ߆߆߽ߦޕ‬ᦨૐ⾓㊄ߩಽᨆߩ㓙ߦ૶↪ߐࠇߥ߆ߞߚߩߪ‫⎇ޔ‬ⓥ⠪߇ 90 ᐕ߹ߢᎺᲤߩ⾓㊄₸ࠍ౉ᚻߢ߈
ߥ߆ߞߚߣ޿߁೙⚂߇ᄢ߈޿ (Brown (1999))‫ޕ‬
Card (1992a) ߪ‫ޔ‬ㅪ㇌⾓㊄ߩ਄᣹ࠍߪߐ߻ 89 ᐕߣ 90 ᐕߢ‫ޔ‬10 ઍߩ㓹↪߇ߤߩࠃ߁ߦᄌ
ൻߒߚ߆‫ޔ‬CPS (Current Population Survey) ࠍ↪޿ߡಽᨆߒߡ޿ࠆ‫ޕ‬1990 ᐕ 4 ᦬ߩᡷᱜߦࠃࠅ‫ޔ‬ㅪ㇌ᦨૐ⾓㊄ߪ 3.35 ࠼࡞߆ࠄ 3.80 ࠼࡞ߦᒁ߈਄ߍࠄࠇࠆ‫ᦨޕ‬ૐ⾓㊄ߩ਄᣹ߦࠃߞ
ߡ‫⾓ޔ‬㊄ߦ⋥ធ⊛ߥᓇ㗀ࠍฃߌࠆߩߪ‫ޔ‬89 ᐕߦ 3.35 ࠼࡞߆ࠄ 3.79 ࠼࡞ߩ⾓㊄ߢ௛޿ߡ޿ߚ
ጀߢ޽ࠆ‫ޕ‬Card (1992a) ߢߪ‫ߩߎޔ‬ጀߩභ߼ࠆഀวߩ㆑޿߇‫ޔ‬89 ᐕ߆ࠄ 90 ᐕߦ߆ߌߡో㓹↪⠪ᢙߩિ߮ߦ‫ߥ߁ࠃߩߤޔ‬ᓇ㗀ࠍਈ߃ߚ߆‫ޔ‬Ꮊߏߣߦಽᨆߒߡ޿ࠆ‫ޕ‬10 ઍߩ㓹↪㊂ࠍઍℂᜰᮡߣߒߡ↪޿ߡ޿ߚᤨ♽೉ಽᨆߣߪ⇣ߥࠅ‫ߩߎޔ‬ᜰᮡߩ૶↪ߪᦨૐ⾓㊄ߩ㓹↪ߦਈ߃ࠆല
ᨐࠍࠃࠅ㞲᣿ߦᝒ߃ߚὐߢ⹏ଔߐࠇࠆ‫ᦨޔߒ߽ޕ‬ૐ⾓㊄ߩ਄᣹ߦࠃࠅ㓹↪㊂߇ᷫዋߔࠆߩߢ
޽ࠇ߫‫ߩߎޔ‬ጀ߇භ߼ࠆഀว߇㜞޿Ꮊ߶ߤ‫ޔ‬㓹↪ߩᷫዋ᏷ߪᄢ߈޿ߪߕߢ޽ࠆ‫߇ߥߒ߆ߒޕ‬ࠄ‫ޔ‬ฦᎺߩ⾓㊄࡟ࡌ࡞ߣ㓹↪㊂ߩჇᷫߩ㑆ߦߪ‫᦭ޔ‬ᗧߥ㑐ㅪᕈߪ⷗ࠄࠇߥ߆ߞߚ‫⺑ߩઁޕ‬᣿ᄌᢙࠍߣࠅᄌ߃ߡ߽‫߷߶ޔ‬ห᭽ߩ⚿ᨐ߇ᓧࠄࠇߡ޿ࠆ‫ᦨޔߪࠇߘޕ‬ૐ⾓㊄ߩ਄᣹߇㓹↪㊂ᷫዋߦᒝ޿ᓇ㗀ࠍਈ߃ߥ޿ߣ޿߁‫ޔ‬቟ቯߒߚ⚿ᨐߢ޽ࠆߣ Card (1992a) ߪ⚿⺰ઃߌߚ‫ޕ‬ߒ߆ߒ‫ޔ‬หߓߊࡄࡀ࡞࡮࠺࡯࠲ࠍ↪޿ߚ Neumark ࠄߩಽᨆߪ‫ᦨޔ‬ૐ⾓㊄ߦߪ㓹↪༚ᄬലᨐ߇޽ࠆߣߩ⚿ᨐࠍዉ޿ߡ߅ࠅ‫ޔ‬એ㒠‫ޔ‬㓹↪༚ᄬലᨐࠍᡰᜬߔࠆ⠪ߣߒߥ޿⠪ߣߩ㑆ߢᄙߊߩ⺰੎߇➅ࠅᐢߍࠄࠇࠆߎߣߦߥࠆ‫ᦨߪߢ▵ᧄޕ‬ૐ⾓㊄߇㓹↪㊂ߦᓇ㗀ࠍਈ߃ߥ޿ߣߒߚ
Card‫ޔ‬Krueger ࠄߩታ⸽⚿ᨐߣ‫ޔ‬㓹↪༚ᄬലᨐ߇ଐὼ޽ࠆߣߒߚ Neumark ࠄߩಽᨆࠍਛᔃ
ߦ⷗ߡ޿ߊߎߣߦߔࠆ‫ޕ‬ࠗ 㓹↪༚ᄬലᨐ߇⹺߼ࠄࠇߥ߆ߞߚታ⸽⚿ᨐᎺ㑆ߩᲧセCard (1992b)‫ޔ‬Card and Krueger (1995) ߪ‫ޔ‬1988 ᐕߦᎺᴺߢᦨૐ⾓㊄ࠍㅪ㇌ᦨૐ⾓㊄ࠃࠅ㜞޿᳓Ḱߦᡷᱜߒߚࠞ࡝ࡈࠜ࡞࠾ࠕᎺߣ‫ޔ‬หᤨᦼߦߪᦨૐ⾓㊄߇ᝪ߃⟎߆ࠇߚ߹߹ߢ޽ߞ
ߚධㇱߩ⻉ᎺࠍᲧセߒߚ߽ߩߢ޽ࠆ‫⺰ޕ‬ᢥߢߪ̌difference-in-differences̍ߣ๭߫ࠇࠆᚻᴺ
ࠍ↪޿ߡ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦߤߩࠃ߁ߥᓇ㗀ࠍਈ߃ߚ߆⷗ߡ޿ࠆ‫̌ޕ‬difference-in-differences̍ߣߪ‫ࠆ޽ޔ‬ೝỗࠍਈ߃ߚ࠻࡝࡯࠻ࡔࡦ࠻࡮ࠣ࡞࡯ࡊ (treatment group) ߣ‫᧦ߩઁޔ‬ઙߪ৻ቯ㧙㧙ߣߒߡೝỗࠍਈ߃ߥ߆ߞߚࠦࡦ࠻ࡠ࡯࡞࡮ࠣ࡞࡯ࡊ (control group) ߣࠍᲧセߒߡ‫ߩߘޔ‬ೝỗߩലᨐࠍ⸘ࠆ⥄ὼ⑼ቇߩಽ㊁ߢᄙߊ↪޿ࠄࠇࠆផቯᴺߢ޽ࠆ‫ߪߢߎߎޕ‬ೝỗ߇ᦨૐ⾓㊄ߩ਄᣹ߣ޿߁ߎߣߦߥࠆ‫̌ޕ‬difference-in-differences̍ߩᦨ߽න⚐ߥផቯᑼߪ‫ޔ‬(Yt2 – Yc2) – (Yt1 – Yc1)

(9),޽ࠆ޿ߪ‫ޔ‬ห୯ߢ޽ࠆ߇‫ޔ‬(Yt2 – Yt1) – (Yc2 – Yc1)

(10),ߢ⴫ߐࠇࠆ‫ޕ‬Card ࠄߩ⺰ᢥߦ߅ߌࠆ Y ߪ‫ޔ‬㓹↪⠪㧙ੱญᲧ₸ߦߥࠆ‫ޕ‬ᷝሼߩ t ߪ̌treatment̍ࠍ‫ޔ‬c ߪ̌control̍ࠍ␜ߒߡ߅ࠅ‫ޔ‬૗ࠄ߆ߩೝỗ߇ਈ߃ࠄࠇߚ߆(t)‫(߆ุޔ‬c)ࠍ⴫ߒߡ޿ࠆ‫ޕ‬⺰ᢥߢߪ೨⠪ߩ t ߇ᦨૐ⾓㊄߇⑼ߖࠄࠇߚᎺࠍ‫ޔ‬ᓟ⠪ߩ c ߇ᦨૐ⾓㊄߇⑼ߖࠄߥ߆ߞߚᎺࠍ
⴫ߔ‫ޔߚ߹ޕ‬ᷝሼߩᢙሼߪߘࠇߙࠇߩᦼࠍ␜ߒ‫ޔ‬2 ߪᦨૐ⾓㊄߇⑼ߖࠄࠇߚᓟߩ 1989 ᐕ‫ޔ‬1
ߪ⑼ߖࠄࠇࠆએ೨ߩ 1987 ᐕࠍ␜ߔ‫(ޕ‬9)‫(ޔ‬10)ᑼߩ⸃㉼ߪ‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ᓟߦᄌൻߒߚ‫ޔ‬ࠞ࡝ࡈࠜ࡞࠾ࠕᎺߩ㓹↪㧙ੱญᲧ₸ߩ߁ߜ‫ᦨߦ☴⚐ޔ‬ૐ⾓㊄ߩߺ߇ਈ߃ߚᓇ㗀߇޿ߊࠄߢ޽
ࠆ߆ࠍ␜ߒߚ߽ߩߣᝒ߃ࠄࠇࠆ‫(ޕ‬9)‫(ޔ‬10)ᑼ߆ࠄߪ‫ޔ‬ੑߟߩᰴర߇⺒ߺขࠇࠆ‫♽ᤨߪߟ৻ޕ‬೉ߩᰴరߢ޽ࠅ‫ᦨޔߪߟ৻߁߽ޔ‬ૐ⾓㊄೙ᐲ߇⑼ߖࠄࠇߚᎺ߆ุ߆‫ࠅ߹ߟޔ‬ᮮᢿ㕙ߢߊߊߞߚᰴరߢ޽ࠆ‫(ޕ‬9)ᑼߪᦨૐ⾓㊄߇⑼ߖࠄࠇߚᎺߣ⑼ߖࠄࠇߥ߆ߞߚᎺ‫ࠅ߹ߟޔ‬ᮮᢿ㕙ߢߩ㓹
↪㊂ߩᏅ⇣ࠍ⺞ߴߡ‫ᤨ⇣ࠍࠇߘޔ‬ὐ㑆ߢᲧセߒߡ޿ࠆ‫(ޕ‬Yt1 – Yc1) ߪ‫ᦨޔ‬ૐ⾓㊄߇⑼ߖࠄࠇ
ࠆએ೨߆ࠄሽ࿷ߒߚᎺ㑆ߢߩᏅ⇣ߣߥࠆ‫(ޕ‬10)ᑼߪ‫ޔ‬Ꮊౝߢߩ㓹↪㊂ߩᤨ♽೉ᄌൻࠍ‫ᦨޔ‬ૐ
⾓㊄߇⑼ߖࠄࠇߚᎺߣߘ߁ߢߥ޿ᎺߣߢᲧセߒߡ޿ࠆ‫(ޕ‬10)ᑼߩ (Yc2 – Yc1) ߪ‫ᦨޔ‬ૐ⾓㊄߇⑼ߖࠄࠇߥ߆ߞߚ႐วߢ߽‫⾓ߚߞߎ⿠ޔ‬㊄ߩ਄᣹ಽߣ⠨߃ࠄࠇࠆ‫ޕ‬หᤨὐߩᏅ⇣ࠍᎺ㑆ߢ‫ޔ‬޽ࠆ޿ߪᎺౝߩᏅ⇣ࠍ⇣ᤨὐ㑆ߢᲧセߒߡᦨૐ⾓㊄ߩലᨐࠍ⸘ࠆߎߣ߆ࠄ‫ߩߎޔ‬ᑼ߇Ꮕ⇣ߩᏅ⇣‫̌ࠅ߹ߟޔ‬difference-in-differences̍ߣ๭߫ࠇࠆᚲએߢ޽ࠆ‫ޕ‬
Card (1992b) ߩ⚿ᨐߪ‫ޔ‬10 ઍߩ㓹↪㧙ੱญᲧ₸ߦ߅ߌࠆ̌difference-in-differences̍߇‫ޔ‬
5.6 ࡄ࡯࠮ࡦ࠻࡮ࡐࠗࡦ࠻㧔ᮡḰ⺋Ꮕߪ 2.3㧕ߣᱜߩ୯ࠍ␜ߒߡ޿ࠆ‫࠾࡞ࠜࡈ࡝ࠞޔߪࠇߎޕ‬ࠕᎺߩ㓹↪㧙ੱญᲧ₸߇‫ߩઁޔ‬ධㇱ⻉ᎺߦᲧߴߡ‫ߩߎޔ‬㑆‫ޔ‬Ⴧടߒߚߎߣࠍᗧ๧ߒߡ޿ࠆ‫ޕ‬ࠞ࡝ࡈࠜ࡞࠾ࠕᎺߩ 10 ઍ㓹↪⠪ߩ߁ߜ 50㧑એ਄߇‫ޔ‬ᣥᦨૐ⾓㊄㗵ߣᣂߒ޿ᦨૐ⾓㊄㗵ߣߩ㑆ߩ⾓㊄ࠍ 1987 ᐕߦᓧߡ޿ߚ‫ᦨࠅ߹ߟޕ‬ૐ⾓㊄ߩ਄᣹ߦࠃࠅ‫ޔ‬ᄙߊߩ 10 ઍ㓹↪⠪߇⾓㊄ᄌᦝߩᓇ㗀ࠍฃߌߚߎߣߦߥࠆ‫ࠍߣߎߩߎޕ‬⠨ᘦߔࠇ߫‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ߦ઻ߞߡ‫ޔ‬㓹↪߇ᄢ᏷ߦ೥ᷫߐࠇߚ੐ታߪߥ߆ߞߚߣ޿߃ࠆ‫ઁޕ‬ᣇ‫ޔ‬ഭ௛⠪ో૕㧔16㧙68 ᱦ㧕ߩ㓹↪㧙ੱญᲧ₸ߩ̌difference-in-differences̍߇㧙0.6 ࡄ࡯࠮ࡦ࠻࡮ࡐࠗࡦ࠻㧔ᮡḰ⺋Ꮕ 0.4㧕ߢ޽ࠅ‫࡝ࠞޔ‬ࡈࠜ࡞࠾ࠕᎺߦ߅ߌࠆో૕ߩ㓹↪ߩᚑ㐳ߪ‫ޔ‬ᲧセᎺߣᲧߴߡ޽߹ࠅ㆑޿߇ߥ߆ߞߚߎߣߦߥ
ࠆ‫ᦨޔߦ߃ࠁޕ‬ૐ⾓㊄ߩ਄᣹߇ 10 ઍߩ㓹↪ࠍჇടߐߖࠆ‫ߪ޿ࠆ޽ޔ‬ዋߥߊߣ߽ᓇ㗀ࠍਈ߃ߥ޿ߣߔࠆ‫⚿ߩߎޔ‬ᨐߪ߆ߥࠅᒝ޿߽ߩߣ⸒߃ࠆ‫ޕ‬ഭ௛ᤨ㑆ߩᄌൻߦߟ޿ߡߪ‫ޔ‬̌difference-in-differences̍߇ 0.3 ࡄ࡯࠮ࡦ࠻࡮ࡐࠗࡦ࠻ߣ㓹↪㧙ੱญᲧ₸ߦᲧߴߡ‫ޔ‬ዊߐߥ୯ࠍ␜ߒߡ޿ࠆ‫ޕ‬
Card (1992b)‫ޔ‬Card and Krueger (1995) ߩ⸘᷹ߢߪ‫ޔ‬10 ઍߩഭ௛⠪ߣห᭽‫ᦨޔ‬ૐ⾓㊄਄㧙㧙᣹ߩᓇ㗀ࠍฃߌ߿ߔ޿ዊᄁᬺߩഭ௛⠪ߣ‫ߦࠄߐޔ‬ዊᄁᬺ㓹↪⠪ో૕ߩ 30㧑ࠍභ߼ࠆ㘶㘩ᬺߩഭ௛⠪ߦߟ޿ߡߩ੐଀⺞ᩏ߽ㅀߴࠄࠇߡ޿ࠆ‫ޕ‬ዊᄁᬺ‫ޔ‬㘶㘩ᬺߣ߽ߦ‫ࠕ࠾࡞ࠜࡈ࡝ࠞޔ‬Ꮊߩ㓹↪㊂߇‫ޔ‬ᲧセᎺߦᲧߴߡᷫዋߒߚߣ޿߁᦭ᗧߥ⚿ᨐߪᓧࠄࠇߡ޿ߥ޿‫ޔߒ߆ߒޕ‬10 ઍో૕ߩ㓹↪ᄌൻߣ⇣ߥࠅ‫ޔ‬Ⴧടߒߡ޿ࠆߣ޿߁߶ߤᒝ޿⚿ᨐߢ߽ߥ޿‫ߩߎޕ‬ᄌൻ߇ߥ޿ߣ޿߁⚿ᨐߪ‫ޔ‬ᕈ೎ߢ߽㗼⪺ߥᏅ⇣ߪ⷗ࠄࠇߥ޿‫ޔߚ߹ޕ‬ㅳ޽ߚࠅഭ௛ᤨ㑆ߦߟ޿ߡߪ 10 ઍߣห᭽ߦ‫ᦨޔ‬ૐ⾓㊄ߪߐ߶ߤᓇ㗀ࠍਈ߃ߡ޿ߥ޿‫ޔߛߚޕ‬㘶㘩ᬺߢ࠴࠶ࡊࠍ߽ࠄߞߡ޿ࠆഭ௛⠪ߦ㑐ߒߡߪ‫ޔ‬ᒰೋ‫ޔ‬Ꮊᦨૐ⾓㊄ߩㆡ↪߆ࠄ㒰ᄖߒߡ‫ޔ‬Ꮊᦨૐ⾓㊄ࠃࠅૐ޿᳓Ḱߩࠨࡉࡒ࠾ࡑࡓ
⾓㊄ߩㆡ↪߇ᬌ⸛ߐࠇߡ޿ߚ‫ޔߪߦ⊛⚳ᦨޕ‬Ꮊߩᴺⷙߦ㆑෻ߒߡ޿ࠆߣߩᜰ៰߆ࠄ‫ޔ‬ᣂⷙᦨ
ૐ⾓㊄ߩ⸳ቯ߆ࠄ 3 ࡩ᦬ᓟߦ‫ࠆ޿ߡߞࠄ߽ࠍࡊ࠶࠴ޔ‬ഭ௛⠪ߦኻߒߡ߽Ꮊᦨૐ⾓㊄ߩㆡ↪߇⟵ോઃߌࠄࠇࠆߩߢߪ޽ࠆ߇‫ޔߦ߃ࠁޕ‬ዊᄁ‫ޔ‬㘶㘩ᬺߢ㓹↪㊂ߦᄌൻ߇⷗ࠄࠇߥ߆ߞߚߎߣ
ߪ‫ޔ‬ഭ௛⠪߇⾓㊄ߦᄌᦝ߇ߥ޿ߣ⠨߃ߚߎߣ߇ේ࿃ߢ޽ࠆ߆߽ߒࠇߥ޿‫ޕ‬ᱷᔨߥ߇ࠄ‫ޔ‬Card(1992b)‫ޔ‬Card and Krueger (1995) ߢߪ‫ޔ‬ᄌൻ߇⿠ߎࠄߥ߆ߞߚߎߣ߇‫ߩߎޔ‬ὐߦේ࿃߇
޽ࠆߩ߆‫ߩઁ߽ߣࠇߘޔ‬ዊᄁ‫ޔ‬㘶㘩ᬺߦ․᦭ߩⷐ࿃ߦࠃࠆ߽ߩߥߩ߆ߦߟ޿ߡ‫ޔ‬ᄙߊߩ⼏⺰ߪߥߐࠇߡ޿ߥ޿‫ޕ‬
 Card ࠄߦࠃࠆ̌difference-in-differences̍ߩផ⸘ߪ‫♽ᤨߩߢ߹ࠇߘޔ‬೉ಽᨆߣߪ⇣ߥࠅ‫ޔ‬⋥ᗵ⊛ߥ⸃㉼ࠍน⢻ߣߒߚ‫⛔ޔࠄ߇ߥߒ߆ߒޕ‬ᓮน⢻ߢ࡜ࡦ࠳ࡓ࡮ࠨࡦࡊ࡝ࡦࠣ߇೨ឭߢ޽
ࠆ⥄ὼ⑼ቇߩታ㛎ߣߪ⇣ߥࠆߚ߼‫ߩߎޔ‬୯ࠍᦨૐ⾓㊄ߩᓇ㗀ߣᝒ߃ࠆߎߣߦߟ޿ߡߪ‫ߊ޿ޔ‬ߟ߆ߩ໧㗴ὐ߇ᜰ៰ߐࠇߡ޿ࠆ‫ޔ߫߃଀ޕ‬Hamermesh (1995) ߢߪ‫ޔ‬એਅߩ 2 ὐ߇ᜰ៰ߐࠇ

⴫㧞㧙㧟 ᦨૐ⾓㊄ߩჇട߇㓹↪ᷫߦߟߥ߇ࠄߥ޿ߣߒߚਥߥታ⸽⚿ᨐ㩷 㪚㪸㫉㪻㩷㩿㪈㪐㪐㪉㪸㪀㩷䊂䊷䉺㩷㪢㪸㫋㫑㩷㪸㫅㪻㩷㪢㫉㫌㪼㪾㪼㫉㩷㩿㪈㪐㪐㪉㪀㩷㪈㪐㪐㪉ᐕ㪉㪃㪊᦬䈫㪈㪈㪃㪈㪉᦬㩷㪈㪐㪐㪇ᐕ㪈㪉᦬㪅㪈㪐㪐㪈ᐕ㪎㪃㪏᦬㩷⪺⠪䉌䈮䉋䉎䊕䊮䉲䊦䊯䉜⪺⠪䉌䈮䉋䉎䊁䉨䉰䉴Ꮊ䇮䊆䉝䊷䊆䊠䊷䉳䊞䊷䉳Ꮊ䇮䊐䉜䊷䉴䊃䊐䊷䊄ᐫ 䈱㔚 ⹤䊐䉜䊷䉴䊃䊐䊷䊄ᐫ 䈱㔚 ⹤⺞ᩏ㩷⺞ᩏ㩷㪈㪐㪏㪐䋭㪈㪐㪐㪇ᐕ㪅㪚㪧㪪㩷䉰䊮䊒䊦䉰䉟䉵㩷

㪚㪸㫉㪻㩷㪸㫅㪻㩷㪢㫉㫌㪼㪾㪼㫉㩷㩿㪈㪐㪐㪋㪀㩷

㪌㪈

㪈㪇㪇

㪊㪌㪎

ⵍ⺑᣿ᄌᢙ㩷

㓹↪⠪䋭ੱญᲧ₸㩷䋨㪈㪇ઍ䋩㩷

䊐䊦䉺䉟䊛឵▚䈚䈢㩷㓹↪⠪ᢙ䋨ኻᢙ䋩䈱ᄌൻ㩷

ᦨૐ⾓㊄䈱㩷
ᜰᮡ㩷

⾓㊄䈏㪊㪅㪊㪌䈎䉌㩷㪊㪅㪎㪐䊄䊦䈱㑆䈮㩷䈅䉎⠪䈱ഀว䋨㪈㪇ઍ䋩㩷ᡷ ᱜ ᦨ ⾓ 䈫ㆡ ↪ ೨ ⾓ ㊄ 䈫ᡷ ᱜ ᦨ ⾓ 䈫ㆡ ↪ ೨ ⾓ ㊄ 䈫䈱䉩䊞䉾䊒㩷
䈱䉩䊞䉾䊒㩷
㫄㪸㫏㩿㪇㪃㩷㫃㫆㪾㩿㪌㪅㪇㪌㪆㪮㪀㩷㪀㩷㫄㪸㫏㩿㪇㪃㩷㫃㫆㪾㩿㪋㪅㪉㪌㪆㪮㪀㩷㪀㩷䊕䊮䉲䊦䊯䉜䊆䉝Ꮊ㩷 㪔㩷㪇㩷ઁ䈱⺑᣿ᄌᢙ㩷㓹↪⠪䋭ੱญᲧ₸䈱ᄌൻ䋨ోᢙ䋩㩷ᄬᬺ₸䈱ᄌൻ㩿ోᢙ㪀㩷䊐䉜䊷䉴䊃䊐䊷䊄䉼䉢䊷䊮䈱 䊐䉜䊷䉴䊃䊐䊷䊄䉼䉢䊷䊮㩷䈱䉺䉟䊒䈮䉋䉎䉻䊚䊷㩷䉺䉟䊒䈮䉋䉎䉻䊚䊷㩷࿾ၞ䉻䊚䊷㩷
ㇺᏒ䈱ੱญ㩷ਥ䈭⚿ᨐ㩷䊆䊠䊷䉳䊞䊷䉳䊷Ꮊ䈪৻ᐫᦨ⾓䈱ᓇ 㗀 䉕ฃ䈔䉎⠪䈱 ⾓㊄䉩䊞䉾䊒䈱ᄢ䈐䈎䈦䈢 ⥩䈅䈢䉍㪈㪅㪎㪉䌾㪈㪅㪊㪈ੱ䈾䈬ഀ ว 䈏ᄙ 䈇 Ꮊ 䈪䇮㓹 ↪ ⠪ ᐫ 䈏 䇮 ᐔ ဋ ⊛ 䈮 㓹 ↪ ㊂ 䉕 㓹↪⠪ᢙ䈏Ⴧട㩷
䋨⾓㊄䉩䊞䉾䊒䈱ᐔဋ୯䈪䈏ᷫዋ䈚䈢䉒䈔䈪䈲䈭䈇䇯 Ⴧ䉇䈚䈩䈇䉎㩷
⹏ଔ䋩㩷

㧙㧙

䊐䊦䉺䉟䊛឵▚䈚䈢㩷㓹↪⠪ᢙ䋨ኻᢙ䋩䈱ᄌൻ㩷ߡ޿ࠆ‫ߪߟ৻ޕ‬ᄌᢙߦ߅ߌࠆᤨ㑆᏷ߩ໧㗴ߢ޽ࠆ‫ޕ‬ℂᗐ⊛ߦߪ Yt1 ߪᦨૐ⾓㊄ߩᓇ㗀ࠍฃߌߡ߅ࠄߕ‫ޔ‬ㅒߦ Yt2 ߪᦨૐ⾓㊄ߩᓇ㗀ࠍචಽߦ෻ᤋߒߡ޿ߥߌࠇ߫ߥࠄߥ޿‫࠾࡞ࠜࡈ࡝ࠞޕ‬ࠕᎺߩ଀ߢߪ‫ޔ‬ᣉⴕ߇ 1988 ᐕ 7 ᦬ߢ޽ࠅ‫ޔ‬ᣉⴕᣣߩ⊒⴫ߪ 1987 ᐕߩ 12 ᦬ߦⴕࠊࠇߚ‫ߛޕ‬߇‫ᦨޔ‬ૐ⾓㊄㗵ᄌᦝߦ㓙ߔࠆ౏⡬ળߪ 1986 ᐕ߆ࠄ㐿߆ࠇ‫ࠅ➅߇⺰⼏ޔ‬㄰ߐࠇߡ޿ߚ‫߃ࠁޕ‬ߦ‫ޔ‬ᐕᦨૐ⾓㊄߇਄᣹ߔࠆߣ޿߁ࠕ࠽࠙ࡦࠬലᨐ߇ 1987 ᐕߦ޽ߞߚߪߕߢ޽ࠅ‫ޔ‬㓹↪ਥߪ㓹↪⺞ᢛࠍᆎ߼ߡ޿ߚ߆߽ߒࠇߥ޿‫ ߚ߹ޕ‬1 ᐕߣ޿߁ᦼ㑆߇‫ޔ‬㓹↪⺞ᢛࠍቢੌߐߖࠆߩߦච
ಽߥᤨ㑆ߢ޽ࠆ߆ᬌ⸛ߩ૛࿾߽޽ࠆ‫ޕ‬ੑߟ⋡ߪ‫ޔ‬ᓧࠄࠇߚ୯߇⚐☴ߦᦨૐ⾓㊄ߩߺߩലᨐࠍ
␜ߒߡ޿ࠆ߆ߣ޿߁ߎߣߢ޽ࠆ‫ࠕ࠾࡞ࠜࡈ࡝ࠞޔ߫߃଀ޕ‬Ꮊߛߌ‫ߪ޿ࠆ޽ޔ‬ㅒߦᲧセᎺߛߌߦᄢ߈ߥ᥊᳇ᄌേ߇⿠ߎߞߡ޿ߚ႐ว‫ޔ‬ផቯ୯ߦߪߘߩᓇ㗀߇฽߹ࠇࠆߎߣߦߥࠆ‫ޕ‬ࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼ᐫߩ㓹↪㊂ᄌൻ
Katz and Krueger (1992) ߪ‫ࠬࠨࠠ࠹ޔ‬Ꮊߩࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼࡮࠴ࠚ࡯ࡦߦ߅޿ߡ‫ᦨޔ‬
ૐ⾓㊄ߩ਄᣹߇㓹↪㊂ߦߤߩࠃ߁ߥᓇ㗀ࠍ෸߷ߒߚ߆ࠍ⺞ᩏߒߚ߽ߩߢ޽ࠆ‫߅ߦࠞ࡝ࡔࠕޕ‬ߌࠆࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼࡮࠴ࠚ࡯ࡦߩ⾓㊄ߪ‫ޔ‬᭎ߨᦨૐ⾓㊄ㄭㄝߩ㗵ߢ⸳ቯߐࠇߡ޿ࠆ‫ޕ‬ᓐࠄߪ‫ޔ‬1991 ᐕ 4 ᦬ߩᡷᱜߢ 4.25 ࠼࡞ߦಾࠅ਄ߍࠄࠇߚᦨૐ⾓㊄ߣ‫ޔ‬ᡷᱜએ೨ߦᐫ஥߇ឭ␜
ߒߡ޿ߚ⾓㊄ߣߩࠡࡖ࠶ࡊߦࠃߞߡ‫ޔ‬ฦࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼ᐫߩ㓹↪㊂⺞▵ߦ㑐ㅪ߇޽ࠆ߆
ࠍಽᨆߒߡ޿ࠆ‫࠼࡯ࡈ࡮࠻ࠬ࡯ࠔࡈߩߤࠎߣ߶ޕ‬ᐫߢߪ‫ ࡓࡑ࠾ࡒࡉࠨޔ‬4ߩ⾓㊄߇૶↪ߐࠇߡ޿ߥ޿‫ޔߡߞࠃޕ‬ᡷᱜ೨ᓟߢ⾓㊄߇ᄢ߈ߊᄌࠊࠆߣ⠨߃ࠄࠇࠆഭ௛⠪ߪ‫ޔ‬೨ߩᦨૐ⾓㊄ߩ᳓Ḱߢ޽ࠆ 3.85 ࠼࡞ࠍឭ␜ߒߡ޿ߚᐫߩᓥᬺຬߢ޽ࠆ‫ޕ‬ᡷᱜએ೨ߦ‫ޔ‬3.85 ࠼࡞ࠍᡰᛄߞߡ޿
ߚᐫߩᐔဋ⊛ߥࡈ࡞࠲ࠗࡓ㓹↪㊂ 5ߩિ߮ߪ‫ޔ‬ኻᢙ୯ߢ 0.16 ߢ޽ࠆ‫ޕ‬ㅒߦ‫ޔ‬ಾࠅ਄ߍએ೨‫ޔ‬
4.25 ࠼࡞ߩ⾓㊄ࠍឭ␜ߒߡ޿ߚᐫߢߪ‫ޔ‬ᐔဋߒߡ‫ޔ‬ኻᢙ୯ߢ 0.16 ߶ߤࡈ࡞࠲ࠗࡓ㓹↪㊂ߩᷫዋ߇⷗ࠄࠇߚ‫ޔߚ߹ޕ‬ᡷᱜᓟߩᦨ⾓㗵‫ޔ‬4.25 ࠼࡞ߣᡷᱜ೨ߩ⾓㊄ߣߩࠡࡖ࠶ࡊࠍ‫ޔ‬㓹↪㊂
ߩᄌൻߦ࿁Ꮻߒߚ⚿ᨐ߽‫⾓ޔ‬㊄ߩᩰᏅ߇ᄢ߈޿߶ߤ㓹↪㊂߇Ⴧ߃ࠆߎߣ߇␜ߐࠇߡ޿ࠆ‫ޕ‬
Katz and Krueger (1992) ߢߪ‫࠻࡯ࡄޔ‬ഭ௛⠪ࠍࡈ࡞࠲ࠗࡓഭ௛⠪ߣห᭽ߦᝒ߃ߚ‫ޔ‬㗡ᢙߢߩ㓹↪⠪ᢙჇടߦߟ޿ߡ߽ಽᨆࠍⴕߞߡ޿ࠆ‫⚿ޕ‬ᨐߪ‫ޔ‬㗡ᢙࠃࠅഭ௛⠪ࠍࡈ࡞࠲ࠗࡓ឵▚ߒߚᣇ߇‫ޔ‬㓹↪㊂ߩિ߮߇ᄢ߈޿ߎߣࠍ␜ߒߡ޿ࠆ‫ᦨޔࠅ߹ߟޕ‬ૐ⾓㊄ᒁ߈਄ߍߦࠃߞߡჇ߃
ߚ㓹↪ߩౝ⸶ߪ‫࠻࡯ࡄޔ‬ഭ௛⠪ࠃࠅ߽ࡈ࡞࠲ࠗࡓᓥᬺຬߩഀว߇ᄢ߈޿ߣ޿߁ߎߣߦߥࠆ‫ޕ‬ࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼ᐫߩ㓹↪㊂ᄌൻߦߟ޿ߡ‫ߦᦝޔ‬ಽᨆࠍ♖✺ൻߒߚ߽ߩ߇ Card andKrueger (1994) ߢ޽ࠆ‫ޕ‬Card and Krueger (1994) ߪ‫࡯ࠫ࡯ࡖࠫ࡯ࡘ࠾ޔ‬Ꮊߣߘࠇߦ㓞ធߔࠆࡍࡦࠪ࡞ࡧࠔ࠾ࠕᎺ᧲ㇱߩᲧセࠍߒߡ޿ࠆ‫࡯ࠫ࡯ࡖࠫ࡯ࡘ࠾ޕ‬Ꮊߢߪ‫ޔ‬ㅪ㇌ᦨૐ⾓㊄ߩಾࠅ਄ߍߦవ㚟ߌߡ‫ޔ‬Ꮊߩᦨૐ⾓㊄ࠍᒁ߈਄ߍߡ޿ߚ‫ߦࠇߎޕ‬ၮߠ߈‫⾓ޔ‬㊄ᡷᱜߩ޽ߞߚ࠾
ࡘ࡯ࠫࡖ࡯ࠫ࡯Ꮊࠍ࠻࡝࡯࠻ࡔࡦ࠻࡮ࠣ࡞࡯ࡊ‫ᦨޔ‬ૐ⾓㊄߇ᝪ߃⟎߆ࠇߚࡍࡦࠪ࡞ࡧࠔ࠾ࠕ

౏ᱜഭ௛ၮḰᴺߦࠃࠅ‫ޔ‬20 ᱦᧂḩߩ㓹↪⠪ߦኻߒߡߪ‫ᦨޔ‬ೋߩ 90 ᣣ㑆‫ޔ‬ㅪ㇌ᦨૐ⾓㊄એਅߩ⾓㊄ߢ㓹߁ߎߣ߇⹺߼ࠄࠇߡ޿ࠆ‫ߩߘޕ‬㓙ߩਅ㒢ࠍ␜ߒߚ߽ߩ߇‫⾓ߩࡓࡑ࠾ࡒࡉࠨޔ‬㊄㗵ߢ޽ࠆ‫ޕ‬
5 ࡄ࡯࠻࠲ࠗࡓഭ௛⠪ߪ‫ޔ‬㗡ᢙߦ 0.58 ࠍ߆ߌߡ㊀ߺઃߌࠍߒߡ޽ࠆ‫ޕ‬4㧙㧙Ꮊࠍࠦࡦ࠻ࡠ࡯࡞࡮ࠣ࡞࡯ࡊߣߒߡ‫⺰ޔ‬ᢥߢߪขࠅᛒߞߡ޿ࠆ‫ޕ‬ᓧࠄࠇߚ⚿ᨐߪ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߚ࠾ࡘ࡯ࠫࡖ࡯ࠫ࡯Ꮊߩ߶߁߇‫ᦨޔ‬ૐ⾓㊄ߩᝪ߃⟎߆ࠇߚࡍࡦࠪ࡞ࡧࠔ࠾ࠕᎺࠃࠅ‫ޔ‬㓹↪ߩિ߮ߪᄢ߈޿ߣ޿߁߽ߩߢ޽ߞߚ‫ࠬࠨࠠ࠹ޔߚ߹ޕ‬Ꮊߩ ੐ ଀ ߣ ห ᭽ ߦ ‫ ⾓ ޔ‬㊄ ࠡ ࡖ ࠶ ࡊ ߩ ᄢ ߈ ߐ ߽ 㓹 ↪ ߩ િ ߮ ߦ ᓇ 㗀 ࠍ ਈ ߃ ߡ ޿ ࠆ ‫ ޕ‬Card andKrueger (1994) ߪ‫⾓ޔ‬㊄ࠡࡖ࠶ࡊߩቯ⟵ߦ㓙ߒߡ‫ࠕ࠾ࠔࡧ࡞ࠪࡦࡍޔ‬Ꮊߩࠡࡖ࠶ࡊࠍ৻ᓞ࠯
ࡠߣ⟎޿ߡ޿ࠆ‫⾓߼ߚߩߘޕ‬㊄ࠡࡖ࠶ࡊߩଥᢙ߆ࠄߪ‫ᦨޔ‬ૐ⾓㊄ߩ⸳ቯ㗵ߦࠃࠆᎺ㑆ߩᏅ⇣ߣ‫ᦨޔ‬ૐ⾓㊄ߣᓧߡ޿ߚ⾓㊄ߩࠡࡖ࠶ࡊߦࠃࠆᎺౝߩᏅ⇣‫ߩߘޔ‬ਔᣇߩലᨐࠍ⏕⹺ߔࠆߎߣ
߇ߢ߈ࠆ‫ޕ‬Ꮊౝߢ⷗ߚ႐ว‫⾓ޔ‬㊄ࠡࡖ࠶ࡊ߇ᄢ߈޿ᐫ߶ߤ㓹↪ߩિ߮߇ᄢ߈ߊ‫ࠬࠨࠠ࠹ޔ‬Ꮊߩ੐଀ࠍ‫ޔ‬ㅊ⹺ߔࠆ⚿ᨐ߇ᓧࠄࠇߡ޿ࠆ‫ߚ߹ޕ‬Ꮊ㑆ߢߺࠆߣ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߚߦ߽㑐ࠊࠄߕ‫࡯ࠫ࡯ࡖࠫ࡯ࡘ࠾ޔ‬Ꮊߩࡈࠔ࡯ࠬ࠻࡮ࡈ࡯࠼ᐫߪࡍࡦࠪ࡞ࡧࠔ࠾ࠕᎺߩߘࠇߦᲧߴߡ‫ޔ‬
1.72 ੱ߆ࠄ 1.31 ੱ߶ߤࡈ࡞࠲ࠗࡓഭ௛⠪ߦ឵▚ߒߡ‫ޔ‬㓹↪⠪߇Ⴧടߒߚߣߩ⚿ᨐࠍᓧߡ޿
ࠆ 6‫ޕ‬
ᦨૐ⾓㊄߇਄᣹ߒߚߦ߽㑐ࠊࠄߕ㓹↪㊂ߪჇടߒߡ޿ࠆߚ߼‫⚿ߩࠄࠇߎޔ‬ᨐߦቢో┹੎ࡕ࠺࡞߇ᒰߡߪ߹ࠄߥ޿ߎߣߪ⸒߁߹ߢ߽ߥ޿‫⾓ޔߪߦࠄߐޕ‬㊄ߩ㆑޿߇ഭ௛⠪ߩ⾰ߩ㆑޿ߦ෻ᤋߐࠇߡ޿ࠆߣ޿߁⇣⾰ᕈࠍ⠨ᘦߒߡ߽‫⾓ޔ‬㊄ߩᒝ೙⊛ߥ਄᣹ߦᔕߓߡ⾰ߩૐ޿ഭ௛⠪߆ࠄ㜞޿ഭ௛⠪߳ߣઍᦧߐࠇࠆ࿑ᑼ߽ᚑࠅ┙ߞߡ޿ߥ޿‫ޕ‬Card and Krueger (1995) ߪ㓹↪㊂
߇ᷫዋߒߥ޿⺑᣿ߣߒߡ‫ޔ‬ᖱႎߩਇቢోᕈࠍขࠅ౉ࠇߚഭ௛ߩ㔛ⷐ⁛භࡕ࠺࡞ࠍឭ␜ߒߡ޿
ࠆ‫ߩࠬ࡝ࠡࠗߚ߹ޕ‬ಽᨆࠍⴕߞߚ Dickens et al. (1999) ߽‫ޔ‬ห᭽ߦᦨૐ⾓㊄ߦ㓹↪༚ᄬലᨐ߇ߥ޿ߎߣࠍ␜ߒߡ޿ࠆ߇‫ޔ‬ᓐࠄߩଐ᜚ߔࠆᨒ⚵߽㔛ⷐ⁛භࡕ࠺࡞ߢ޽ࠆ‫ޔࠄ߇ߥߒ߆ߒޕ‬㔛ⷐ⁛භࡕ࠺࡞ߪቢో┹੎ࡕ࠺࡞ߦᲧߴߡ◲ẖߥࡕ࠺࡞ߢߪߥ޿‫࠼࡯ࡈ࡮࠻ࠬ࡯ࠔࡈޕ‬ᐫߩ޽ࠆ৻ᐫ߇⾓㊄ࠍ਄ߍណ↪ࠍჇ߿ߒߚߣߒߡ‫ᦨߩઁޔ‬ૐ⾓㊄ᬺ⒳߽หߓࠃ߁ߥⴕേࠍߣࠆߩ
߆ (Welch (1994)) ߥߤ‫ޔ‬㔛ⷐ⁛භࡕ࠺࡞ߪᄙߊߩ⚻ᷣቇ⠪߆ࠄ⾥หࠍᓧߡ޿ࠆࠊߌߢߪߥ޿‫ޕ‬࠙ 㓹↪༚ᄬ߇⹺߼ࠄࠇߚታ⸽⚿ᨐ
ᦨૐ⾓㊄ߪ㓹↪㊂ߦᓇ㗀ࠍਈ߃ߥ޿ߣߒߚ‫ޔ‬Card ࠄߩᜰ៰ߦኻߒߡ‫ޔ‬Neumark andWascher (1992) ߢߪ‫ޔ‬10㧑ߩᦨૐ⾓㊄ߩ਄᣹߇ 1 ߆ࠄ 2㧑߶ߤ⧯ᐕጀߩ㓹↪㊂ࠍᷫዋߐߖ
ࠆߣߩ⚿ᨐࠍᓧߡ޿ࠆ‫ޔߪࠇߎޕ‬70 ᐕ߆ࠄ 80 ᐕઍߦ߆ߌߡⴕࠊࠇߚᤨ♽೉ಽᨆߣ‫ޔ‬หߓ⚿ᨐߢ޽ࠆ‫⚿ߩߎޕ‬ᨐߦᓥ߁ߥࠄ߫‫ޔ‬ଐὼ‫ᦨޔ‬ૐ⾓㊄߇㓹↪ߦਈ߃ࠆᓇ㗀ߦߟ޿ߡ‫ޔ‬ቢో┹੎ࡕ࠺࡞ߦࠃࠆ⺑᣿߇น⢻ߣߥࠆ‫ޕ‬ᓐࠄߩផ⸘ߪ‫ޔ‬1973 ᐕ߆ࠄ 1989 ᐕ߹ߢߩ Current Population Survey ࠍടᎿߒߡᎺߏߣ
ߩࡄࡀ࡞ࠍ૞ᚑߒ‫ޔ‬ಽᨆࠍⴕߞߚ߽ߩߢ޽ࠆ‫ޕ‬ផ⸘ᑼߪ
Eit = ǩXit + ǪMWit + ǫYit +ǬSit +ǭit6࠾ࡘ࡯ࠫࡖ࡯ࠫ࡯Ꮊࠍ⾓㊄ࠡࡖ࠶ࡊߩᐔဋ୯ߢ⹏ଔߒߡ޿ࠆ‫ޕ‬

㧙㧙

(11),

ߣ‫ޔ‬ᑼߩ᭴ㅧ⥄૕ߪ‫♽ᤨޔ‬೉ಽᨆߣ߶߷หߓ߽ߩߢ‫ޔ‬E ߪ㓹↪⠪㧙ੱญᲧ₸ࠍ‫ޔ‬X ߪ᥊᳇ᄌേߩᜰᮡࠍ‫ޔ‬MW ߪᦨૐ⾓㊄ߩᜰᮡ㧔ࠞࠗ࠷࡮ࠗࡦ࠺࠶ࠢࠬ㧕ࠍߘࠇߙࠇ␜ߔ‫ޕ‬ᷝ߃ሼߩ i
ߪᎺࠍ t ߪᐕࠍ⴫ߔ‫ ߚ߹ޕ‬Y ߣ S ߪ‫ࠇߙࠇߘޔ‬ᐕߣᎺߩ࿕ቯലᨐߢ޽ࠆ‫࠲࡯࠺࡮࡞ࡀࡄޕ‬೑↪ߦ߅ߌࠆ೑ὐߩ৻ߟߪ‫♽ᤨޔ‬೉ಽᨆߢ໧㗴ߣߥߞߡ޿ߚ‫ޔ‬᥊ᴫᗵߥߤฦᎺߦ․⇣ߥᏒ႐Ⅳ
ႺߩᏅ⇣ࠍ‫ޔ‬S ߦࠃߞߡ޽ࠆ⒟ᐲขࠅ㒰ߊߎߣ߇น⢻ߦߥߞߚߎߣߢ޽ࠆ‫ޕ‬߹ߚ‫ޔ‬Neumark and Wascher (1992) ߢߪ‫ޔ‬Ꮊߩᦨૐ⾓㊄߇ㅪ㇌⾓㊄ࠃࠅ㜞޿Ꮊߦ߅޿ߡ‫ޔ‬
ㅪ㇌⾓㊄ߦઍࠊࠅᎺߩᦨૐ⾓㊄ࠍࠞࠗ࠷࡮ࠗࡦ࠺࠶ࠢࠬߩਛߢ૶↪ߒߡ޿ࠆ‫ߪߢࠞ࡝ࡔࠕޕ‬Ꮊᴺߦࠃߞߡ‫ᦨޔ‬ૐ⾓㊄߇ㅪ㇌ߩߘࠇࠃࠅ㜞޿᳓Ḱߦ⸳ቯߐࠇߡ޿ࠆᎺ߇޽ࠆ‫ޔߌࠊࠅߣޕ‬1980 ᐕઍᓟඨએ㒠‫ޔ‬ㅪ㇌ᦨૐ⾓㊄એ਄ߩ㗵ࠍ⸳ቯߒߚᎺ߇Ⴧടߒߡ߈ߚ‫ޕ‬ㅪ㇌ᦨૐ⾓㊄ࠍਅߦ૞ᚑߒߚ౒ㅢߩ MW ߛߌߢฦᎺߩ㓹↪ߩേ߈ࠍ⷗ࠆߎߣߪ‫ᦨޔ‬ૐ⾓㊄ߩലᨐࠍ⛘ኻ୯ߦ߅޿ߡㆊᄢߦផቯߒߡߒ߹߁ߎߣߦߥࠆ‫ޔߒ߆ߒޕ‬Card et al. (1994) ߪ‫ޔ‬Ꮊ↥ᬺߩࠞࡃ࡟࠶
ࠫߦ㑐ߔࠆ࠺࡯࠲߇ Neumark ࠄߩ MW ߦ฽߹ࠇߡ޿ߥ޿ߚ߼‫ᦨޔ‬ૐ⾓㊄߇෸߷ߔ⌀ߩലᨐࠃࠅ߽‫ޔ‬ଐὼ‫⛘ޔ‬ኻ୯ߢㆊᄢផ⸘ߦߥߞߡ޿ࠆߣᜰ៰ߒߡ޿ࠆ‫ޕ‬ߐߡ‫ޔ‬Neumark ߣ Wascher ߦࠃࠆ৻ㅪߩ⺰ᢥߢߪ‫ޔ‬ዞᬺߣዞቇߩ㑐ଥߦᦨ߽㊀ὐ߇߅߆ࠇߡ޿ࠆ‫ޔߕ߹ޕ‬Neumark and Wascher (1992)ߢߪ‫(ޔ‬11)ᑼߩቯᑼൻߦ߅޿ߡ‫ޔ‬ዞቇ₸ࠍ฽߼ࠆ߆ุ߆ߣ޿߁ߎߣ߇໧㗴ߣߐࠇߚ‫ޕ‬ᓐࠄߩዞቇ₸ࠍ⺑᣿ᄌᢙߦട߃ߚផ⸘ߢߪ‫ᦨޔ‬ૐ
⾓㊄ߩ਄᣹ߪ 10 ઍߩ㓹↪㊂ࠍᷫࠄߔᓇ㗀߇⷗ࠄࠇࠆ߇‫ޔ‬ㅒߦ⺑᣿ᄌᢙ߆ࠄขࠅ㒰ߊߣ‫ޔ‬10ઍߩ㓹↪㊂ߦᓇ㗀ࠍਈ߃ߥߊߥࠆ‫ࠍࡦ࡚ࠪ࡯ࠤ࡝ࡊࡦࠗޔߜࠊߥߔޕ‬ዉߊ㓙‫ޔ‬ዞቇ₸ߪ᳿ቯ⊛ߥᓎഀࠍߒߡ޿ࠆߎߣ߇ಽ߆ࠆ‫ߒ߽ޕ‬ዞቇ₸߇㓹↪㊂ߣᒝ޿⋧㑐ࠍᜬߟߩߢ޽ࠇ߫‫☴⚐ޔ‬ߥᦨૐ⾓㊄ߩലᨐࠍ⷗ࠆߚ߼ߦߪ‫ޔ‬ᒰὼ‫ޔ‬ዞቇ₸ࠍࠦࡦ࠻ࡠ࡯࡞ߔࠆᔅⷐ߇޽ࠆ‫ޔߒߛߚޕ‬ዞቇ₸ߪᦨૐ⾓㊄ߩᓇ㗀߽ฃߌࠆน⢻ᕈ߇޽ࠅ 7‫ߦࠄߐޔ‬ዞቇߣዞᬺߪੑ⠪ᛯ৻⊛ߥ߽ߩߢ޽
ࠆ߆ࠄ‫ޔ‬ዞቇ₸ 8ࠍ⺑᣿ᄌᢙߦട߃ࠆߎߣߢౝ↢ᕈߩࡃࠗࠕࠬ߇↢ߓࠆෂ㒾ᕈ߇޽ࠆ‫ޔߚ߹ޕ‬ዞቇ₸ߪഭ௛ଏ⛎஥ߩⷐ࿃ߢ޽ࠆ‫ޔߦ߃ࠁޕ‬㔛ⷐߩ೙⚂ߢ㓹↪㊂߇᳿߹ࠆቢో┹੎ࡕ࠺࡞ࠍ
೨ឭߣߒߚ(11)ᑼߢߪ‫ߩߣ޿ߥߪߢ߈ߴߔ↪૶ޔ‬ᛕ್߽ߥߐࠇߡ޿ࠆ (Card et al. (1994))‫ޕ‬ߘࠇߢ߽‫ޔ‬ዞቇ₸ࠍ⺑᣿ᄌᢙߣߒߡណ↪ߒߚℂ↱ߣߒߡ‫ޔ‬ᓐࠄߪᰴߩ 2 ὐࠍ޽ߍߡ޿ࠆ‫ޕ‬
1 ὐ⋡ߪ‫ޔ‬ዞቇ₸ࠍ⺑᣿ᄌᢙߦട߃ߥ޿ߣ‫ᦨޔ‬ૐ⾓㊄߇ 10 ઍߩ㓹↪㊂ߦߪᓇ㗀ࠍਈ߃ߕ‫ޔ‬20
ઍߩ㓹↪㊂ߦߩߺ⽶ߩᓇ㗀ࠍ޽ߚ߃ࠆ‫ᦨޕ‬ૐ⾓㊄ߩᓇ㗀ࠍⵍࠅ߿ߔ޿ߪߕߩ 10 ઍߩ㓹↪㊂
߇ 20 ઍࠃࠅ߽‫ޔ‬ᱜߦߒࠈ⽶ߦߒࠈᓇ㗀ࠍฃߌߡ޿ߥ޿ߩߪవ㛎⊛ߦ⠨߃ߡ߅߆ߒ޿‫ޕ‬2 ὐ⋡ߪ‫⺑ⵍޔ‬᣿ᄌᢙߩ㓹↪㧙ੱญᲧ₸ߦᄢ߈ߥᓇ㗀ࠍਈ߃ࠆߣ⠨߃ࠄࠇࠆో૕ߩᄬᬺ₸ࠍ‫⺑ޔ‬᣿ᄌᢙ߆ࠄ㒰ᄖߒߡ߽ዞᬺ₸ߩଥᢙߪߐ߶ߤᄌൻߒߥ޿‫ࠅ߹ߟޕ‬ౝ↢ᕈߩࡃࠗࠕࠬߪ‫ߤ߶ߐޔ‬ᄢ߈ߊߪߥ޿‫ޔࠄ߆ߣߎߩࠄࠇߎޕ‬ዞቇ₸ࠍᄌᢙߦട߃ࠆߎߣߦࠃߞߡ↢ߓࠆౝ↢ᕈߩࡃࠗࠕࠬࠃࠅ߽‫ޔ‬ዞቇ₸ࠍ⋭ߊߎߣߦࠃࠅᑼߩ․ቯൻࠍ⺋ࠆ߶߁߇㊀ᄢߥ໧㗴ߢ޽ࠆߣ⚿⺰ઃߌ

7
8

Ehrenberg and Marcus (1982) ߢߪ‫ᦨޔ‬ૐ⾓㊄ߩዞቇ₸ߦਈ߃ࠆᓇ㗀߇᣿⏕ߥ߽ߩߣߥߞߡ޿ߥ޿‫ޕ‬
Neumark and Wascher (1992) ߢߩዞቇ₸ࠍ⴫ߔᄌᢙߪ‫̌ޔ‬Population of Age Group in School̍ߣ޿߁ฬ⒓ߢ↪޿ࠄࠇߡ߅ࠅ‫ޔ‬ዞቇߒߡ޿ߡ‫ߟ߆ޔ‬ዞᬺ߽ߒߡ޿ߥ޿⠪ߩੱᢙߢ޽ࠆ‫ޕ‬㧙㧙ߡ޿ࠆ‫ޕ‬ߐࠄߦ‫ޔ‬Neumark and Wascher (1995a,1995b) ߪ‫ᦨޔ‬ૐ⾓㊄߇‫ޔ‬ዞቇ߿ዞᬺߥߤ 10 ઍߩᵴേ⁁ᘒߦਈ߃ࠆᓇ㗀ࠍ⋥ធផ⸘ߒ‫ޔ‬㓹↪㊂Ⴧᷫߩਛりߦߟ޿ߡ⸒෸ߒߡ޿ࠆ‫ޔߪߢߎߘޕ‬ᦨૐ⾓㊄ߩ਄᣹ߪዞቇ₸ࠍᷫࠄߒ‫ޔ‬ㅒߦዞᬺ߽ዞቇ߽ߒߡ޿ߥ޿⠪ߩഀวࠍჇടߐߖߡ޿ࠆ‫ޕ‬
߹ߚ 10 ઍో૕ߩ㓹↪㊂ߪ‫ޔ‬௖߆ߦᷫߢ޽ࠆ‫⚿ߩߎޕ‬ᨐ߆ࠄዉ߆ࠇࠆ઒⺑ߣߒߡߪ‫ޔ‬ዞቇߒߡ޿ߚ⠪߇ቇᩞࠍㄉ߼‫ޔ‬ഭ௛Ꮢ႐ߦ಴ߡ⡯ࠍតߒߡ޿ࠆ‫ޔߪ޿ࠆ޽ޕ‬ዞቇߖߕߦ௛޿ߡ޿ߚ
⠪߆ࠄᦨ⾓ᡷᱜએ೨ߪዞቇߒߡ޿ߚ⠪߳ߣഭ௛⠪ߩઍᦧ߇⿠ߎߞߚ‫ߩߎޕ‬ੑߟ߇⠨߃ࠄࠇࠆ‫ޕ‬ߎࠇࠄߩ઒⺑ࠍᬌ⸽ߔࠆߚ߼‫ޔ‬10 ઍߩᵴേ⁁ᘒ߇‫ᦨޔ‬ૐ⾓㊄ߩ਄᣹ᓟߤߩ⁁ᘒ߳ߣᄌൻߔࠆ
น⢻ᕈ߇ᒝ߆ߞߚ߆‫ޔ‬ᓐࠄߪᓧࠄࠇߚផ⸘୯߆ࠄߘߩ⏕₸ࠍ⸘▚ߒߡ޿ࠆ‫⚿ޕ‬ᨐࠍ⷗ࠆ㒢ࠅ‫ޔ‬਄⸥ߩ⡯តߒߣઍᦧ‫ޔ‬ਔᣇߩ઒⺑ߣ߽ᡰᜬߐࠇߡ޿ࠆ‫ޕ‬ߒ߆ߒߥ߇ࠄ‫ᦨޔ‬ૐ⾓㊄ߣዞቇ₸ߩ㑆ߦߎࠇ߶ߤᒝ޿⽶ߩ⋧㑐߇޽ࠆߩߥࠄ߫‫ޔ‬Neumark
and Wascher (1992) ߩ㓹↪ߦ⽶ߩᓇ㗀ࠍਈ߃ࠆߣ޿߁⚿ᨐߪ‫ࠅߥ߆ޔ‬ਇ቟ቯߥ߽ߩߦߥࠆ
ߢ޽ࠈ߁‫ޔߚ߹ޕ‬Neumark and Wascher (1995a)ߦ߅޿ߡ‫ޔ‬ᓥ᧪໧㗴ߣߐࠇߡ߈ߚ㓹↪⠪ߩੱญߦභ߼ࠆഀว⥄૕ߪ‫ߤࠎߣ߶ޔ‬ᄌൻߒߡ޿ߥ޿‫⺰ߩߎޕ‬ᢥߢߪ‫ޔ‬10 ઍࠍዞᬺ‫ޔ‬㓹↪‫ޔ‬㕖ዞᬺߣಽߌߡ޿ࠆߩߢ‫ߩߢ߹੹ޔ‬ታ⸽⎇ⓥਛߢᦨ߽ዞቇ₸ߩᓇ㗀ࠍࠦࡦ࠻ࡠ࡯࡞ߒߚ߽ߩߣ
⸒߃ࠆ‫ޔߚ߹ޕ‬Brown (1999) ߩ‫ᦨޟ‬ૐ⾓㊄߇ዞቇ₸ࠍᷫࠄߔലᨐ߇޽ࠆߣߔࠇ߫‫ߪࠇߘޔ‬㓹↪ߩᷫዋࠃࠅ߽㊀ⷐߥߎߣߢ޽ࠆ‫ߩߣޠ‬ᜰ៰ߪ‫ޔ‬ታߦᅷᒰߥ߽ߩߢ޽ࠈ߁‫ޔࠃߖߦࠇߕ޿ޕ‬ዞቇ₸ߪᘕ㊀ߦᛒࠊߥߌࠇ߫ߥࠄߥ޿ߎߣߪ‫⚻ޔ‬ᷣቇ⠪ߩ㑆ߢᗧ⷗ߪ৻⥌ߒߡ޿ࠆ‫ޔߛߚޕ‬ߘࠇ᡿ߦ‫ߦ߁ࠃߩߤޔ‬ᛒ߁߆ߴ߈߆ߦߟ޿ߡߪ‫ߛᧂޔ‬ᗧ⷗ߩ৻⥌ࠍ⷗ߡ޿ߥ޿‫ޕ‬⴫㧞㧙㧠 ᦨૐ⾓㊄ߩ਄᣹߇㓹↪ᷫߦߟߥ߇ࠆߣߒߚታ⸽⚿ᨐ㩷㩷㪥㪼㫎㫄㪸㫉㫂㩷㪸㫅㪻㩷㪮㪸㫊㪿㪼㫉㩷㩿㪈㪐㪐㪉㪀㩷䊂䊷䉺㩷㪈㪐㪎㪊䋭㪈㪐㪏㪐 ᐕ䈱 㪚㪧㪪㩷㩿㪤㪸㫉㪺㪿㪀㩷䉰䊮䊒䊦䉰䉟䉵㩷
㪎㪌㪈㓹↪⠪䋭ੱญᲧ₸㩷ⵍ⺑᣿ᄌᢙ㩷䋨㪈㪇 ઍ䇮㪈㪍䋭㪉㪋 ᱦ䋩㩷ᦨૐ⾓㊄䈱㩷
䉦䉟䉿䊶䉟䊮䊂䉾䉪䉴㩷ᜰᮡ㩷䋨Ꮊᦨ⾓䉅⠨ᘦ䋩㩷ዞቇ₸㩷ᄬᬺ₸㩷ઁ䈱⺑᣿ᄌᢙ㩷Ꮊ䉻䊚䊷㩷ᐕᰴ䉻䊚䊷㩷
㪈㪇䋦䈱ᦨ⾓਄᣹䈲 㪈㪇 ઍ䈱㓹↪㊂䉕 㪈 䈎䉌 㪉䋦ᷫዋ䇯㩷ห䈛䈒䇮㪉㪇 ઍ೨ඨ䈱㓹↪㊂䉕 㪈㪅㪌⚿ᨐ㩷䈎䉌 㪉䋦ᷫዋ䇯㩷ዞቇ₸䉕ᄌᢙ䈎䉌㒰ᄖ䈜䉎䈫䇮ᦨ⾓䈲⽶䈱ലᨐ䉕ᜬ䈢䈭䈇䇯㩷㪛㪼㪼㫉㪼㩷㪼㫋㩷㪸㫃㩷㩿㪈㪐㪐㪌㪀㩷㪈㪐㪏㪌䋭㪈㪐㪐㪉 ᐕ䈱 㪚㪧㪪㩷㪋㪇㪏㓹↪⠪䋭ੱญᲧ₸㩷䋨ኻᢙ୯䇮㪈㪇 ઍ䋩㩷㪐㪇 ᐕ䈫 㪐㪈䋭㪐㪉 ᐕ䈱ᐕᰴ䉻䊚䊷㩷㪈㪌䋭㪍㪋 ᱦ↵ᕈ䈱㓹↪⠪䋭ੱญᲧ₸䋨ኻᢙ୯䋩㩷
Ꮊ䉻䊚䊷㩷䉺䉟䊛䊶䊃䊧䊮䊄㩷㪐㪈 ᐕ 㪋 ᦬䈱ᦨ⾓਄᣹䈲䇮↵䈪 㪇㪅㪎䋦䇮ᅚ䈪 㪇㪅㪈㪈䋦䇮㪈㪇 ઍ䈱㓹↪㊂䉕
ᷫዋ䈘䈞䉎ലᨐ䈏䈅䈦䈢䇯㩷㩷㩷㩷

Deere et al. (1995) ߩផቯ߽߹ߚ‫ᦨޔ‬ૐ⾓㊄߇㓹↪㊂ߦ⽶ߩᓇ㗀ࠍਈ߃ࠆߣߔࠆ߽ߩߢ޽㧙㧙ࠆ‫ޔߪߢߎߘޕ‬1991 ᐕߦ߅ߌࠆᦨૐ⾓㊄ߩ਄᣹߇‫ޔ‬਄᣹߇ߥ߆ߞߚ႐วߦᲧߴߡ 7㧑߶ߤ‫ޔ‬
10 ઍߩ↵ᕈߩ㓹↪㊂ࠍ᛼ߒਅߍࠆലᨐ߇ᓧࠄࠇߡ޿ࠆ‫ޔࠄ߇ߥߒ߆ߒޕ‬ૐ⾓㊄ഭ௛⠪߇ᄙߊ௛޿ߡ޿ߚᎺߢ‫ޔ‬ᄢ᏷ߥ㓹↪ߩᷫዋ߇޽ࠆ߆ߣ޿߃߫‫ᦨޔߚ߹ޕ޿ߥ߽ߢ߁ߘޔ‬ૐ⾓㊄ߩㄭߊߢ௛޿ߡ޿ࠆഀว߇㜞޿ᅚᕈߩ㓹↪ߪ‫↵ޔ‬ᕈ߶ߤᷫዋߒߡ޿ߥ޿‫ޔࠅ߹ߟޕ‬㓹↪ߩჇᷫߪ‫ޔ‬නߦᦨૐ⾓㊄ߩሽ࿷ߩߺߦࠃߞߡ᳿߹ࠆ߽ߩߢߪߥ޿ߣ⸒߁ߎߣߦߥࠆ‫ޔߪߣߎߩߎޕ‬Kennan (1995) ߢ߽ᜰ៰ߐࠇ‫ޔ‬10 ઍߩ㓹↪₸ߪ৻ࡩ᦬න૏ߢᄢ߈ߊᄌേߒߡ߅ࠅ‫ߩߘޔ‬ਛ߆ࠄᦨૐ⾓㊄਄᣹ߦࠃࠆലᨐߩߺࠍዉ߈ߛߔߎߣߪ࿎㔍ߢ޽ࠆߣߒߡ޿ࠆ‫ޕ‬Deere et al.
(1995) ߢߪ‫⺞ޔ‬ᩏᦼ㑆ߦ߅ߌࠆ 10 ઍߩ㓹↪㊂ߩേ߈ߪ‫ޔ‬㓹↪⠪ో૕ߩჇᷫ‫ࠅ߹ߟޔ‬ഭ௛㔛ⷐߩჇᷫߦࠃߞߡᒝߊᒁߞᒛࠄࠇߚ߽ߩߢ޽ࠆߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬80 ᐕઍߩᓟඨߪ‫ޔ‬ഭ௛㔛ⷐߩિ߮ߦᡰ߃ࠄࠇ‫ޔ‬ૐ⾓㊄ഭ௛⠪ߩ㓹↪߽િ߮ߡ޿ߚ‫ߒ߆ߒޕ‬90 ᐕઍೋ㗡ߩਇ᥊᳇ߦࠃࠅ‫ޔ‬ഭ௛㔛ⷐߪ⪭ߜㄟ߻‫ޔ޿઻ߦࠇߘޕ‬ૐ⾓㊄ഭ௛⠪ߩ㓹↪㊂߽ᷫ
ዋߒߚ‫ߩߎޕ‬ᷫዋ᏷ߪ‫ޔ‬㓹↪ߩ᜛ᒛᦼߦ߅ߌࠆჇടߣኻᾖ⊛ߥ߽ߩߢߪߥߊ‫ࠅࠃޔ‬ᄢ߈ߥᷫዋ߇޽ߞߚ‫ోޔࠅ߹ߟޕ‬૕ߩഭ௛㔛ⷐߦࠃߞߡ⺑᣿߇ߟ߆ߥ޿ߎߩᷫዋಽ߇‫ޔ‬90 ᐕઍߦ਄᣹
ߒߚᦨૐ⾓㊄ߦࠃࠆᓇ㗀ߢ޽ࠆߣ⚿⺰ઃߌߡ޿ࠆ‫ޕ‬Brown (1999) ߪਔ⠪ߦ߅ߌࠆലᨐߩ㆑
޿ߪ‫ᦨޔ‬ૐ⾓㊄ߩᜰᮡߦࠃࠆ㆑޿ߦ޽ࠆߣᜰ៰ߒߡ޿ࠆ‫ޕ‬Card and Krueger (1994) ߢߪ‫ޔ‬ᄌᢙ߇Ꮊ࿕᦭ߩᓇ㗀ࠍ෻ᤋߔࠆ߇‫ޔ‬Deere et al. (1995) ߢߪ‫ᦨޔ‬ૐ⾓㊄߇਄߇ߞߚᐕߩᐕᰴ
࠳ࡒ࡯ᄌᢙࠍ૶ߞߡಣℂߒߡ޿ࠆߩߢ‫ޔ‬Ꮊ࿕᦭ߩᓇ㗀ࠍᛠីߢ߈ߕో࿖৻ᓞߩᛒ޿ߣߥߞߡ
޿ࠆ‫⚿ߩߢߎߎޔࠃߖߦࠇߕ޿ޕ‬ᨐ߽‫ᦨޔ‬ૐ⾓㊄ߩ㓹↪ߦਈ߃ࠆᓇ㗀߇ቯᑼൻߦࠃߞߡᄢ߈
ߊᏀฝߐࠇࠆߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬ ⾓㊄ಽᏓߦਈ߃ࠆᓇ㗀੹߹ߢ⚫੺ߒߚታ⸽ಽᨆߪ‫ᦨޔ‬ૐ⾓㊄߇਄᣹ߒߚ㓙‫ޔ‬ẜ࿷⊛ߦߤߩߊࠄ޿ߩ㓹↪㊂߇ᄌൻߔࠆ߆ߦὶὐࠍวࠊߖߡ߈ߚ߽ߩߢ޽ߞߚ‫ᦨޔࠅߥ⇣ߪߣࠇߎޕ‬ૐ⾓㊄ࠍ⾓㊄ಽᏓߣߩ㑐ଥߢᝒ߃ߚ⺰ᢥ߽ሽ࿷ߔࠆ‫ޕ‬એਅߢߪ‫⺰ߩࠄࠇߎޔ‬ᢥࠍ⚫੺ߔࠆ‫ޕ‬
ᦨૐ⾓㊄߇⾓㊄ಽᏓߦਈ߃ࠆᓇ㗀ࠍߺࠆ೨ߦ‫☨ޔ‬࿖ߢߪߤߩࠃ߁ߥዻᕈࠍᜬߟ㓹↪⠪߇ᦨ
ૐ⾓㊄ߩᓇ㗀ࠍฃߌߡ޿ࠆߩ߆ࠍ◲නߦ⸅ࠇߡ߅ߎ߁‫ޕ‬ᓇ㗀ࠍฃߌࠆጀߦߟ޿ߡߪ
Bernstein and Schmitt (2000) ߇ 1999 ᐕߩ CPS ࠺࡯࠲ࠍ◲ẖߦ߹ߣ߼ߡ޿ࠆ‫ޕ‬એਅߪ‫ߘޔ‬ߎߢᓧࠄࠇߡ޿ࠆ⍮⷗ߢ޽ࠆ‫ޕ‬1㧕‫ޔ‬ㅪ㇌޽ࠆ޿ߪᎺߩᦨૐ⾓㊄ࠃࠅ 1 ࠼࡞೨ᓟߩ⾓㊄ࠍᓧߡ޿ࠆ㓹↪⠪ߪ‫ోޔ‬ഭ௛⠪ߩ
8.7㧑ࠍභ߼ࠆ‫ޕ‬એᓟ‫ߩߎޔ‬ጀࠍᦨૐ⾓㊄ߩᓇ㗀ࠍฃߌࠆ㓹↪⠪ߣ๭߱‫ޕ‬2㧕‫ᦨޔ‬ૐ⾓㊄ߩᓇ㗀ࠍฃߌࠆ㓹↪⠪ߩ⚂ 71㧑ߪ‫ޔ‬20 ᱦએ਄ߢ޽ࠆ‫ ߦ․ޕ‬20 ᱦએ਄ߩᅚᕈߩභ߼ࠆഀว߇ᄢ߈ߊ‫ޔ‬ో૕ߩ⚂ 45㧑ࠍභ߼ࠆ‫ޕ‬3㧕‫ޔ‬ㅳ 35 ᤨ㑆એ਄ߩࡈ࡞࠲ࠗࡓഭ௛⠪߇‫ޔ‬ᓇ㗀ࠍฃߌࠆഭ௛⠪ߦභ߼ࠆഀวߪ 48㧑ߢ޽ࠆ‫ޕ‬4㧕‫ޔ‬ᓇ㗀ࠍฃߌࠆഭ௛⠪ߩ߁ߜ‫ޔ‬32㧑߇ሶଏࠍ᦭ߒߡ޿ࠆ‫߹ޕ‬ߚሶଏ߇޿ࠆ‫ߩࠄࠇߎޔ‬ഭ௛⠪ߩ߁ߜ 63㧑ߪ‫ޔ‬ኅ⸘ᚲᓧ߇ 25,000 ࠼࡞ߦḩߚߥ޿‫ޕ‬ߐߡ‫ᦨޔ‬ૐ⾓㊄߇ᣂߚߦ⸳ቯߐࠇࠆߣ‫⸳ߩߘޔ‬ቯ㗵એਅߢ௛޿ߡ޿ߚഭ௛⠪ߪ‫ޔ‬ᣂߚߦ⸳㧙㧙⟎ߐࠇߚᦨૐ⾓㊄㗵એ਄ߩ⾓㊄ࠍᓧࠆ߆‫ᦨߩߘޔ‬ૐ⾓㊄㗵એਅߩ᳓Ḱߦߣߤ߹ࠆ߆‫ޔ‬⡯ࠍᄬ߁߆ߦᝄࠅಽߌࠄࠇࠆߎߣߦߥࠆ‫ᦨޕ‬ૐ⾓㊄ߪߎߩࠃ߁ߦ⾓㊄ಽᏓࠍಾᢿߔࠆߚ߼‫ᦨߩߘޔ‬ૐ⾓㊄㗵ߩㄭㄝߢߪ‫ޔ‬ᒰὼ‫ߥ߆ࠄߛߥޔ‬ಽᏓ߇ឬ߆ࠇࠆߎߣߪߥ޿‫☨ޕ‬࿖ߩ⾓㊄ಽᏓߪ‫ᦨޔ‬
ૐ⾓㊄㗵ߩㄭㄝߢߎ߱⁁ߩ⓭⿠߇↢ߓߡ޿ࠆ‫ߣࠢࠗࡄࠬߪࠇߎޕ‬๭߫ࠇࠆ⃻⽎ߢ޽ࠆ‫ޕ‬Meyer
and Wise (1983a,b)‫ޔ‬Card and Krueger (1995)‫ޔ‬Currie and Fallick (1996) ╬ߢ‫ޔ‬10 ઍߩ
⾓㊄ಽᏓߦ߅޿ߡ‫ᦨޔ‬ૐ⾓㊄㗵ߢߎ߱߇⏕⹺ߐࠇߡ޿ࠆ‫ޕ‬ߎ߱ߩਛߦߪ‫ᦨޔ‬ૐ⾓㊄߇ሽ࿷ߒߥߌࠇ߫‫ࠇߘޔ‬એਅߩ⾓㊄ࠍฃߌขߞߡ޿ߚߪߕߩഭ௛
⠪߽฽߹ࠇࠆ‫ޕ‬ቢో┹੎‫ߪ޿ࠆ޽ޔ‬ੑㇱ㐷ࡕ࠺࡞ߦᓥ߃߫‫⾓ޔ‬㊄ߩ਄᣹ߦࠃߞߡ㓹↪⠪ߪ੹߹ߢࠃࠅഭ௛㔛ⷐࠍᷫࠄߒߡ޿ࠆߪߕߢ޽ࠆ‫ޕ‬Meyer and Wise (1983a, b)ߪ‫ᦨޔ‬ૐ⾓㊄ߦࠃࠆ㓹↪ᯏળߩ༚ᄬࠍ‫ޔ‬ផቯߒߚಽᏓ߆ࠄᓧࠄࠇࠆᦨૐ⾓㊄એਅߩኒᐲߣ‫ޔ‬ታ㓙ߩಽᏓߦ߅ߌ
ࠆᦨૐ⾓㊄એਅߩኒᐲߣߩᏅ⇣ߦ᳞߼‫ޔ‬㓹↪㊂߇ᷫዋߒߚߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬ᓐࠄ߇ផቯߒ
ߚ‫ᦨޔ‬ૐ⾓㊄߇ሽ࿷ߒߥ޿႐วߩ⾓㊄ಽᏓߪ‫ᦨޔ‬ૐ⾓㊄㗵એ਄ߩ⾓㊄ࠍ߽ࠄߞߡ޿ࠆഭ௛⠪ߩዻᕈ߆ࠄ‫ޔ‬ኻᢙᱜⷙಽᏓࠍᗐቯߒߚ߽ߩߢ޽ࠆ‫ޔߒ߆ߒޕ‬Meyer and Wise (1983a, b)ߩផቯᴺߪ‫ޔ‬Dickens et al. (1998) ߦࠃߞߡᛕ್ߐࠇߡ޿ࠆ‫ޔߪߟ৻ޕ‬ಽᏓో૕ߦ߅ߌࠆᦨૐ⾓㊄ߩᵄ෸ലᨐࠍ⠨ᘦߦ޿ࠇߡ޿ߥ޿ߚ߼‫ޔ‬㓹↪༚ᄬലᨐࠍㆊᄢផ⸘ߒߡ޿ࠆ‫ޔߚ߹ޕ‬ಽᏓᒻផቯߩ㓙ߦኻᢙᱜⷙಽᏓࠍ઒ቯߔࠆߎߣߪ೙⚂߇ᒝߔ߉ࠆ‫ᦨޔߡߒߘޕ‬ዕᴺߦࠃࠆផቯߢߪ‫ޔ‬
Meyer and Wise ߩ㓹↪ലᨐߪᔅߕ⽶ߣߥࠆ‫ޕ‬Dickens et al.ߪ‫ߩࠄࠇߎޔ‬ὐࠍୃᱜߒߡࠗࠡ
࡝ࠬߩಽᨆࠍⴕߞߡ޿ࠆ‫⚿ޕ‬ᨐߪਇ቟ቯߥ߽ߩߢ޽ࠅ‫ޔ‬㓹↪༚ᄬലᨐ߇޽ࠆߣߪ⹺߼ࠄࠇߡ
޿ߥ޿‫ޕ‬
㔛ⷐ஥ߩ┙႐߆ࠄ⷗ࠇ߫‫ޔߪࡓ࠭࠾ࠞࡔࠆߔ↢⊒߇ࠢࠗࡄࠬޔ‬ડᬺ߇ᦨ߽ૐ޿ࠦࠬ࠻ߢഭ
௛⠪ࠍ㓸߼ߡ޿ࠆߎߣߦᏫ⌕ߔࠆ‫ޕ‬ㅒߦ‫ޔ‬Holzer et al. (1991) ߪ‫ᦨޔ‬ૐ⾓㊄㗵ߣߪ⇣ߥࠆ߇
ᦨૐ⾓㊄㗵ㄭㄝߩ㗵ࠍឭ␜ߒߡ޿ࠆ⡯ࠃࠅ‫ᦨޔ‬ૐ⾓㊄㗵ߜࠂ߁ߤߩ㗵ࠍឭ␜ߒߡ޿ࠆ⡯ߩᣇ߇‫ޔ‬ᄙߊߩഭ௛⠪ࠍ߭߈ߟߌߡ޿ࠆߎߣࠍ␜ߒߡ޿ࠆ‫ᦨޕ‬ૐ⾓㊄೙ᐲߪ‫ޔ‬⡯ߩౝኈ߿ⅣႺࠍ
ᄌ߃ࠆߎߣߥߊഭ௛⠪ߩ⾓㊄ࠍᐩ਄ߍߔࠆߣ‫ޔ‬ᓐࠄߪߎߩ⚿ᨐࠍ⸃㉼ߒߡ޿ࠆ‫ޕ‬
DiNardo et al. (1996) ߪ‫ᦨޔ‬ૐ⾓㊄߇⾓㊄ᩰᏅߦ߽ᓇ㗀ࠍਈ߃ࠆߎߣࠍ␜ߒߚ⺰ᢥߢ޽ࠆ
9‫ᦨޕ‬ૐ⾓㊄ㄭㄝߦ⌕⋡ߒߡ޿ࠆ਄⸥ߢ⚫੺ߒߚ⺰ᢥߣߪ⇣ߥࠅ‫ޔ‬ಽᏓో૕ߩࠪࡈ࠻ࠍ⷗ߡ޿

ࠆ‫ޔߕ߹ޕ‬ᓐࠄߪઁߩ᧦ઙࠍ৻ቯߣߒߡ‫ޔ‬ታ⾰ᦨૐ⾓㊄߇ 1979 ᐕߩ᳓Ḱߩ߹߹ߢ޽ߞߚ႐
ว‫ޔ‬1988 ᐕߩ⾓㊄ಽᏓ߇ߤߩࠃ߁ߦឬ߆ࠇࠆ߆ࠍផቯߒߚ‫ޔߡߒߘޕ‬ታ⾰ᦨૐ⾓㊄߇ਇᄌߢ޽ࠆߎߩ઒ᗐ⊛ߥ 88 ᐕߩಽᏓߣ‫ޔ‬ታ㓙ߩ 88 ᐕߩಽᏓࠍᲧセߔࠆߎߣߢ‫ᦨޔ‬ૐ⾓㊄߇⾓㊄ಽᏓߦਈ߃ࠆᓇ㗀ࠍᝒ߃ߡ޿ࠆ‫ޕ‬1980 ᐕઍߪ‫ߤࠎߣ߶ޔ‬ㅪ㇌ᦨૐ⾓㊄ߩᡷᱜ߇ⴕࠊࠇߕ‫ߩߎޔ‬ᤨᦼ‫ᦨޔ‬ૐ⾓㊄ߪታ⾰⊛ߦૐਅߒߚ‫⾓ޔࠅ߹ߟޕ‬㊄ߩਅ㒢୯߇ಽᏓߩᏀߦ⒖േߒߚߎߣߦߥ
ࠆߚ߼‫⾓ޔ‬㊄ಽᏓߪ᜛ᄢߔࠆߎߣ߇੍ᗐߐࠇࠆ‫ޕ‬ታ㓙‫ޔ‬1988 ᐕߪ 1979 ᐕߦᲧߒߡಽᏓߩᮡ

91980 ᐕઍߩࠕࡔ࡝ࠞߢ‫⾓ޔ‬㊄ᩰᏅ߇᜛ᄢߒߚℂ↱ߣߒߡㅢᏱᜰ៰ߐࠇߡ޿ࠆߩߪ‫ޔ‬࿖㓙⾏ᤃ (Murphy andWelch,1991)‫ޔ‬ᛛ⢻஍ะဳߩᛛⴚㅴᱠ (Bound and Johnson,1992) ߥߤߦࠃࠆ‫ޔ‬㜞ᛛ⢻ഭ௛⠪ߦኻߔࠆ㔛ⷐߩ㜞߹ࠅߢ޽ࠆ‫ޕ‬㧙㧙Ḱ஍Ꮕ߇Ⴧടߒߡ߅ࠅ‫⾓ޔ‬㊄ᩰᏅߪჇᄢߒߡ޿ࠆ‫ޕ‬ഭ௛㔛⛎߿ᢎ⢒᳓Ḱ╬‫⾓ޔ‬㊄ߦᓇ㗀ࠍਈ߃ࠆߘߩઁߩⷐ࿃ࠍࠦࡦ࠻ࡠ࡯࡞ߒߚ႐ว‫ޔ‬ᮡḰ஍Ꮕ߇Ⴧടߒߚ߁ߜ‫↵ޔ‬ᕈߢ⚂ 17㧑‫ޔ‬ᅚᕈߢ⚂ 24㧑ߪታ⾰ᦨૐ⾓㊄ૐਅߩነਈಽߢ޽ࠆߣ޿߁‫ޕ‬Card and Krueger (1995) ߽ᦨૐ⾓㊄߇਄᣹ߒߚ 1990 ᐕߣ 1991 ᐕࠍߪߐ߻‫ޔ‬1989 ᐕ߆ࠄ 1992 ᐕ߹ߢߩ⾓㊄ಽᏓࠍᲧセߒߡ޿ࠆ‫ᦨޕ‬ૐ⾓㊄ߩᡷᱜߪૐ⾓㊄ഭ௛⠪ߩ⾓㊄ࠍ਄᣹ߐߖߡ߅ࠅ‫ߚ߹ޔ‬Ꮊ㑆ߢߩ⾓㊄ᩰᏅ߽❗ዊߒߡ޿ࠆ‫ ޔߪࠇߎޕ‬DiNardo et al. (1996) ߩ⚿ᨐߣห᭽‫ᦨޔ‬ૐ⾓㊄ߩሽ࿷߇⾓㊄ᩰᏅߩ᜛ᄢࠍᛥ߃ࠆ௛߈߇޽ࠆߎߣࠍ␜ߒߚ߽ߩߣ޿߃ࠆ‫ޕ‬㧟 ᣣᧄߩታ⸽⎇ⓥએਅߢ‫ޔ‬ᣣᧄߦ߅ߌࠆᦨૐ⾓㊄ߩታ⸽ಽᨆߩ⚿ᨐߦߟ޿ߡ◲නߦ⸅ࠇࠆ‫ޔߦ߼ߓߪߕ߹ޕ‬ᦨૐ⾓㊄߇ࡄ࡯࠻⾓㊄ߦኻߒߡ᦭ലߥਅᡰ߃ߣߥߞߡ޿ࠆߩ߆ߤ߁߆ߦ㑐ߔࠆ⼏⺰ߦߟ޿ߡߺߡ޿ߊ‫ޕ‬એਅߢ⺑᣿ߔࠆ⺰ᢥߢߪ‫ޔ‬ᔅߕߒ߽‫ޟ‬ਅᡰ߃ലᨐ‫ߡ޿ߟߦޠ‬෩ኒߦቯ⟵ߠߌ߇ߥߐࠇߡ޿ࠆ⸶ߢߪߥ޿߇‫ޔ‬ਅᡰ߃ߣߪએਅߩ࿑ 2㧙4 ߩࠃ߁ߥࠗࡔ࡯ࠫ࿑ࠍᗐቯߔࠆߩ߇ᅷ
ᒰߢߪߥ޿߆ߣᕁࠊࠇࠆ‫ޕ‬࿑ 2㧙4 ߪ‫❑ޔ‬ゲߦഭ௛⠪ഀวࠍ‫ޔ‬ᮮゲߦ⾓㊄ࠍ␜ߔ࿑ߢ޽ࠅ‫ޔ‬࿑ਛߦ❑ߦ৻ᧄ㐳ߊᒁ߆ࠇߡ޿ࠆ✢߇ᦨૐ⾓㊄㗵ࠍ␜ߒߡ޿ࠆ‫ޕ‬ਅᡰ߃ߣߪ‫ᦨޔ‬ૐ⾓㊄㗵ㄭㄝߦᄙߊ⾓㊄߇㓸Ⓧߒߡ߅ࠅ‫ޔ‬ᱜߦૐ⾓㊄ഭ௛⠪ߩ⾓㊄ࠍਅ߆ࠄᡰ߃ߡ޿ࠆࠃ߁ߥ⁁ᴫࠍᜰߒ␜ߔߣ⠨߃ࠄࠇࠆ‫ޔߚ߹ޕ‬૬ߖߡ‫ᦨޔ‬ૐ⾓㊄㗵ᧂḩߩ⾓㊄㗵ߣ޿߁ߩߪᴺᓞ㆑෻ߢ޽ࠆߚ
߼ᦨૐ⾓㊄㗵ᧂḩߩഭ௛⠪ഀวߪዊߐߊ‫ᦨߤ߁ࠂߜޔ‬ૐ⾓㊄㗵ࠍႺߦፗ߇ಾࠅ┙ߞߚࠃ߁ߥ
⁁ᴫߣߥࠆߎߣ߇⠨߃ࠄࠇࠆ‫ޕ‬࿑㧞㧙㧠 ਅᡰ߃ലᨐߩࠗࡔ࡯ࠫ࿑

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․ߦᅚᕈࡄ࡯࠻࠲ࠗࡑ࡯ߦߟ޿ߡ‫ᦨޔ‬ૐ⾓㊄㗵߇ਅᡰ߃ലᨐࠍ᦭ലߦ⊒ើߒߡ޿ࠆߣߔࠆ
⺰ᢥߦ᳗ἑ㧔1997㧕߇޽ࠆ‫ޕ‬᳗ἑ㧔1997㧕ߪ‫ޔ‬ᔅߕߒ߽ᦨૐ⾓㊄ߦ㑐ߔࠆಽᨆߦਥ⌒ࠍ⟎޿ߚ⺰ᢥߢߪߥ޿ߌࠇߤ߽‫ޔ‬1990 ᐕߩ‫ࡓࠗ࠲࠻࡯ࡄޡ‬ഭ௛⠪✚วታᘒ⺞ᩏ‫ߩޢ‬୘␿ࠍ↪޿ࠆߎߣߦࠃࠅ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛⠪ߩ⾓㊄߇࿾ၞ೎ᦨૐ⾓㊄㗵ߣ߈ࠊ߼ߡኒ⌕ߒߚ㑐ଥߦ޽ࠆߣ
ਥᒛߒߡ޿ࠆ‫ޕ‬ᅚᕈࡄ࡯࠻࠲ࠗࡓഭ௛⠪ߩ⾓㊄ࠍో࿖ 8 ࿾ၞߦಽߌߡࡅࠬ࠻ࠣ࡜ࡓߦߔࠆߣ‫ޔ‬㑐᧲࡮ਛㇱࠍ㒰ߊߘߩઁߩ࿾ၞߦߟ޿ߡ‫ޔ‬ᅚᕈࡄ࡯࠻࠲ࠗࡓഭ௛⠪ߩ⾓㊄ߩᦨ㗫୯ߪᒰ⹥࿾
ၞߦ߅ߌࠆᦨૐ⾓㊄ߦ߶߷৻⥌ߒ‫ޔ‬ᅚᕈ⾓㊄ߪߘߩ๟ㄝߦ㓸ਛߒߡ޿ࠆ‫ޔߚ߹ޕ‬ᅚᕈߩ႐ว
ߪ‫ޔ‬ධ㑐᧲๟ㄝ࿾඙ࠍ㒰ߊߣ‫ᦨޔ‬ૐ⾓㊄ࡊ࡜ࠬ 100 ౞એౝߦ‫⾓ޔ‬㊄ಽᏓߩㆊඨߩ 53㧑߇ࠞࡃ࡯ߐࠇࠆߎߣߦߥࠆ‫⾓ޔߦࠄߐޕ‬㊄㑐ᢙߦᢎ⢒ᐕᢙ‫ޔ‬ൕ⛯ᐕᢙ‫↥ޔ‬ᬺ‫ޔ‬࿾ၞߥߤߩ⺑᣿ᄌᢙߦട߃ߡㇺ㆏ᐭ⋵೎࡮↥ᬺ೎ߩᦨૐ⾓㊄㧔ߩኻᢙ㧕ࠍ౉ࠇࠆߣ‫ߩߘޔ‬ଥᢙ߇ᱜߣߥࠆߎߣ
߆ࠄ‫ᦨޔ‬ૐ⾓㊄೙ߪࡄ࡯࠻࠲ࠗࡓഭ௛⠪ߩ⾓㊄ߦኻߒߡ᦭ലߥਅᡰ߃ߣߒߡᯏ⢻ߒߡ޿ࠆߣ
⚿⺰ઃߌߡ޿ࠆ‫ޕ‬৻ᣇ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛⠪ߩ⾓㊄ߦኻߒߡ‫ᦨޔ‬ૐ⾓㊄߇ਅᡰ߃ᯏ⢻ࠍ᦭ലߦ⊒ើߒߡ޿ࠆ
ߩߪ㒢ࠄࠇߚ⋵ߦߟ޿ߡߢ޽ࠆߣߔࠆ⼏⺰߽޽ࠆ‫ޕ‬ዊේ㧔2000㧕‫ޔ‬቟ㇱ㧔2001㧕ߪ‫ߩߘޔ‬ઍ⴫⊛ߥ⺰ᢥߢ޽ࠆ‫ޕ‬ዊේ㧔2000㧕ߪ‫ޔ‬1995 ᐕߩ‫ࡓࠗ࠲࠻࡯ࡄޡ‬ഭ௛⠪✚วታᘒ⺞ᩏ‫ߩޢ‬୘␿ࠍ↪޿ࠆߎߣߦ
ࠃࠅ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛⠪ߩ⾓㊄ಽᏓߦ㑐ߔࠆࠞ࡯ࡀ࡞ផቯࠍⴕߞߡ޿ࠆ‫࡞ࡀ࡯ࠞޕ‬ផቯߣߪ‫⾓ޔ‬㊄ߩಽᏓဳߩ․ቯൻࠍⴕࠊߥ޿⾓㊄ಽᏓߩផ⸘ᣇᴺߢ޽ࠅ‫◲ޔ‬නߦ޿߃߫‫ࠣ࠻ࠬࡅޔ‬࡜ࡓߩ᫔ߩⷺࠍ߹ࠆ߼ߡࠃࠅᐔṖൻߒߚಽᏓࠍ↢ߺ಴ߔផ⸘ᣇᴺߢ޽ࠆ‫⾓ޕ‬㊄ಽᏓߦ↢ߓࠆࠦࡉࠍ್ᢿၮḰߣߒߡ‫ޔ‬ർᶏ㆏‫␹ޔ‬ᄹᎹ⋵‫ޔ‬ንጊ⋵‫ޔ‬㐳㊁⋵‫ޔ‬ᗲ⍮⋵‫ޔ‬ਃ㊀⋵‫ޔ‬੩ㇺᐭ‫౓ޔ‬ᐶ⋵‫ޔ‬ጊญ⋵‫ޔ‬ᗲᇫ⋵‫⑔ޔ‬ጟ⋵‫ޔ‬ᴒ✽⋵ߥߤߢᦨૐ⾓㊄߇⾓㊄ߩਅᡰ߃ࠍߒߡ޿ࠆߣߒߡ޿
ࠆ‫ޕ‬቟ㇱ㧔2001㧕ߪ‫ޔ‬1990 ᐕ෸߮ 1995 ᐕߩ‫ࡓࠗ࠲࠻࡯ࡄޡ‬ഭ௛⠪✚วታᘒ⺞ᩏ‫ߩޢ‬୘␿ࠍ↪
޿ࠆߎߣߦࠃࠅ‫ޔ‬ਥߣߒߡᰴߩࠃ߁ߥ⚿ᨐࠍዉ߈಴ߒߡ޿ࠆ‫ޕ‬Ԙ ৻ㇱ࿾ၞ㧔ർᶏ㆏‫ޔ‬㕍᫪‫ޔ‬ᣂẟ‫ޔ‬੩ㇺ‫ޔ‬ጊญ‫਻ޔ‬Ꮊߩฦ⋵㧕ߦ߅޿ߡߪ‫ᦨޔ‬ૐ⾓㊄߇
޽ࠆ⒟ᐲࡄ࡯࠻࠲ࠗࡓഭ௛⠪ߩ⾓㊄ߩਅᡰ߃ߣߒߡ᦭ലߥ೙⚂ߣߥߞߡ޿ࠆ‫ߪࠇߎޕ‬ㆊ
෰ 20 ᐕ߶ߤߩ㑆ߦ‫ޔ‬࿾ၞ೎ᦨૐ⾓㊄߇߈ࠊ߼ߡ⎬⋥⊛ߦ⸳ቯߐࠇߡ߈ߚߎߣߦේ࿃߇޽ࠆ‫ޕ‬ԙ ㆊ෰ߩ⎇ⓥߢߪ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛⠪ߩ⾓㊄ߪᦨૐ⾓㊄ߦ߈ࠊ߼ߡㄭ޿᳓Ḱߦ㓸ਛߒߡ߅ࠅ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛ߪᦨૐ⾓㊄ߦਅᡰ߃ߐࠇߚૐ⾓㊄ഭ௛ߢ޽ࠆߣ⼏⺰ߐࠇߡ߈ߚ‫ߩߢߎߎޔࠄ߇ߥߒ߆ߒޕ‬ಽᨆ⚿ᨐߪߎߩࠃ߁ߥ⹺⼂ߦ⇼໧ࠍᛩߍ߆ߌࠆ߽ߩߢ޽ࠆ‫ޕ‬⏕߆ߦ‫৻ޔ‬ㇱߩ⋵ߦ߅޿ߡߪ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛⠪ߩ⾓㊄߇ᦨૐ⾓㊄ઃㄭߦᄙߊ㓸ਛߒߡ޿ࠆ‫ࡓࠗ࠲࠻࡯ࡄޔߒ߆ߒޕ‬ഭ௛⠪ߩᄙߊ߇௛ߊᄢㇺᏒ࿾ၞߦ߅޿ߡߪ‫ࠗ࠲࠻࡯ࡄޔ‬ࡓഭ௛⠪ߩ⾓㊄ߪ࿾ၞ೎ᦨૐ⾓㊄ࠃࠅ 20㨪30㧑㜞޿ߩ߇৻⥸⊛ߢ޽ࠆ‫ޕ‬Ԛ ↥ᬺ೎ᦨૐ⾓㊄㧔⵾ㅧᬺ߅ࠃ߮ዊᄁᬺ߇ኻ⽎㧕ߪ‫ޔ‬࿾ၞ೎ᦨૐ⾓㊄ࠃࠅ߽⾓㊄ߩਅᡰ㧙㧙߃ߣߒߡߩᯏ⢻߇㜞޿ߣ⠨߃ࠄࠇࠆ‫ޕ‬߹ߚ‫ޔ‬቟ㇱ㧔2004㧕ߪ‫⾓ޡޔ‬㊄᭴ㅧၮᧄ⛔⸘⺞ᩏ‫․ߩޢ‬೎㓸⸘⚿ᨐࠍ↪޿ࠆߎߣߦࠃࠅ‫ޔ‬࿾ၞ೎ᦨૐ⾓㊄ߩਅᡰ߃ലᨐߦߪ࿾ၞߦࠃࠅᄢ߈ߥᏅߩ޽ࠆߎߣࠍౣ⏕⹺ߒߡ޿ࠆ‫ޔߚ߹ޕ‬ᦨૐ⾓㊄ߪ‫ޔ‬ㇺᏒㇱߢ᦭ലߥ೙⚂ߦߥߞߡ޿ߥ޿௑ะ߇޽ࠆ߇‫ޔ‬࿾ᣇߦࠃߞߡߪਛዊડᬺߢ
࿾ၞ೎ᦨૐ⾓㊄߇᦭ലߥ೙⚂ߦߥߞߡ޿ࠆߣߎࠈ߽޽ࠆߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬એ਄ߩᦨૐ⾓㊄ߦ㑐ߔࠆਅᡰ߃ലᨐߦ㑐ߔࠆ⎇ⓥએᄖߦ߽‫ޔ‬ᰴߩࠃ߁ߥ⎇ⓥ⚿ᨐ߇ᢔ⷗ߐ
ࠇࠆ‫ޕ‬◉Ⴆ㧔1989㧕ߪ‫ ╙ޔ‬8 ┨‫ޟ‬ᅚሶࡄ࡯࠻ഭ௛ߣᦨૐ⾓㊄೙‫ߩޠ‬ਛߢ‫ࡓࠗ࠲࠻࡯ࡄޔ‬ഭ௛⠪ߩ
⾓㊄᳿ቯ߇ᦨૐ⾓㊄㗵ߣᒝߊ࡝ࡦࠢߒߡ޿ࠆߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬
Kawaguchi and Yamada㧔2004㧕ߪ‫ޔ‬ኅ⸘⚻ᷣ⎇ⓥᚲߩ‫ޡ‬ᶖ⾌↢ᵴߦ㑐ߔࠆࡄࡀ࡞⺞ᩏ‫ޢ‬ࠍ↪޿ࠆߎߣߦࠃࠅ‫ޔ‬ᰴߩࠃ߁ߥ⚿ᨐࠍዉ߈಴ߒߡ޿ࠆ‫ᦨޔߕ߹ޕ‬ૐ⾓㊄߇ᅚᕈߩૐ⾓㊄ഭ௛⠪㧔⾓㊄߇‫ޔ‬೨ᐕߩᦨૐ⾓㊄ߣኻ⽎ᐕߩᦨૐ⾓㊄ߩ㑆ߦಽᏓߔࠆഭ௛⠪ࠍᜰߔ㧕ߩ⾓㊄ߦᓇ㗀ࠍ෸߷ߔ߆ߤ߁߆ᬌ⸛ߒߡ޿ࠆ߇‫ޔ‬ᓇ㗀ࠍ෸߷ߐߥ޿ߣ޿߁⚿ᨐ߇ᓧࠄࠇߚ‫ޔߚ߹ޕ‬ᅚᕈࠍኻ⽎ߣߒᦨૐ⾓㊄ߩ㓹↪ߦ෸߷ߔലᨐࠍ⸘᷹ߒߡ޿ࠆ߇‫ࠍࡊ࡯࡞ࠣ࡮࡞࡯ࡠ࠻ࡦࠦޔ‬ૐ⾓㊄ഭ௛⠪ߣߒߚ႐ว╬ߦߟ޿ߡ‫ᦨޔ‬ૐ⾓㊄߇⽶ߩ㓹↪ലᨐࠍ෸߷ߔߎߣࠍ␜ߒߡ޿ࠆ‫ޕ‬߹ߚ‫␹ޔ‬ઍ㧔2004㧕ߪ‫ᦨޔ‬ૐ⾓㊄೙ᐲߩᄌㆫㆊ⒟߿ᦨૐ⾓㊄೙ࠍ߼ߋࠆ໧㗴ὐߦߟ޿ߡ൮
᜝⊛ߦ⺰ߓߡ޿ࠆ‫ޕ‬

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