Q td —g db (6.21)
6.4.2.Thgt nghiep, tich 1u9 va ph5n ph
MO hinh Goodwin [1967] cung cap mQt cach nhin khac ve mQt dOng thai ma to c6 thd nhi;in day mQt s6 dac tinh cita chting trong cac mO hinh vi mO kinh to luting, khi dau to phu thuOc vao kha nang sinh 16i (lqi
nhuan). MO hinh nay co hai dac tinh: do la mot trong cac mO hinh tang truOng co tinh chu ky hie'm hoi; va Ong thai dia mO hinh nay chi dim duy nhat vao su bien thien cna su phan chia thu nhap chit khong dim vao he só tang toe nhu mO hinh Kalecki. Ta có the coi m6 hinh nay la mot trong nhiing clang tai tien thuOc mO hinh phi can bang sau Keynes (Kaldor [1957]). Thi truong hang hod luOn can bang va tat ca loi nhuan deu de tiet kiem (hoac &du tu), tat ca tien Wong deu throe dem di tieu dung. Thi truOng lao Ong, ngtroc lai khOng can bang va tY le tang truOng muc luong thirc phu thuOc vao that nghiep (dubng tong Phillips). 1(5, thuat san xuat chi la nhan to phy bOi vi khi thi trubng lao Ong can bang thi sir phan chia thu nhap la on dinh va to lai c6 m6 hinh tang truOng clang Harrod - Domar - Kaldor; lac do lai suit tiet kiem se bang mot phan loi nhuan trong san xuat.
Chu trinh la ket qua sir hien thien muc phan chia (xem mO to hinh 6.8). Hinh 6.8a mO to co cau cna mO hinh. HInh 6.8b mO to cac giai (loan cita chu trinh. Khi phdn loi nhuan Ion (VI du diem A), thi ddu to se cao va tang traOng san xuat throe thilc day. Dieu do lam tang viec lam va giam that nghiep (mai ten huong phia trai trong hinh 6.8b, khi 11>11*). Tai diem A, tY le that nghiep cao hon gia tri can bang u*, thi mut luong that giam; dieu do lam tang phan loi nhuan trong san xuat (mai ten haing len phia tren trong hinh 6.8b khi a>0). Tii dau chu 14, viec giam that nghiep an den t5, le that nghiep thap ho'n diem u* (diem B) va phdn loi nhuan giam clan den viec tang truOng bi cham lai. Khi phan loi nhuan Chap hon 11* tin ink tang tru'Ong try' nen thap hon mire tang truerng cung lao clOng (diem C), tY le that nghiep lai bat dau tang len va khi \AA qua ty le that nghiep u* thi tY le tang tien luong bi cham lai; phan loi nhuan dan &in dime thiet lap trO lai (diem D). MO hinh Goodwin co dac al-1h rieng biet: dua ra chu trinh han the dac tinh ty' duy tri ma nhCrng (lac tinh nay phy thuOc vao cac dieu kien ban ddu.
VI tat ca cac co cau deu du'oc thiet lap data tren su dieu chinh muc luong thirc dOi yeti nan that nghiep nen m6 hinh Goodwin dua ra chu trinh khao sat trong mot tiled ky clai va sir hien thien cita viec phan chia khOng tao nen &Ong thai chY yeu cua chu trinh kinh re. Viec ket hop m6 hinh Goodwin va mO hinh truOc day la rat me.itn cfr:o de giai thich dOng
thai cila van de phi lam phat canh tranh. Ty le that nghiep cao se de Ong len mdc tang truong luong, dieu do lam tang Ong th6i kha nang canh tranh va 10 nhuan cua doanh nghiep. L0 the canh tranh va tang dau tu phai thtic day viec tang lqi nhuan; dieu dO day nhanh teic dO tang twang va keo theo viec giam nan that nghiep trong khoang th6i gian do.