CPI - Thước đo lạm phát

NGHIEN CL/U TRAO DOI ( So 11(64) - 2008 )

CPI - THi/QfC DO LAM PHAT

TS. Pham Kim Van

Chi sd gia tieu diing CPI (Consumer Price

Index) la mdt chi tieu thdng ke phan anh mirc do

va xu budng bien ddng ciia gia ca chung cua mdt

sd lugng cd djnh cac loai hang hda, djch vy (dugc

ggi la "rd" hang hda) da dugc chgn dai dien cho

tieu diing, phyc vu ddi sdng ciia cac tac nhan trong

nen kinh te, qua thdi gian.

Ve Iy thuyet, khi xem xet sy bien ddng cua mdt

chi tieu kinh te nao dd, cac nhan td khdng djnh

nghien cuu phai dugc cd djnh Iai d mdt ky - ggi la

quyen sd cua chi sd, nham loai bd anh hudng ciia

cac nhan td khdng can nghien ciru tdi nhan td cdn

Iai. Vi vay, khi nghien ciru sy bien ddng cua gia ca

ndi chung cac mat bang ngudi ta thudng cd djnh

lugng hang hda tieu thy hoac ca cau chi tieu la

nhtfng chi tieu cd lien quan tdi gia ca ndi chung

ciia cac mat hang d ky gdc hoac ky bao cao, do

vay cdng thirc tinh chi sd gia cd the viet dudi dang

sau: ; ..

- Chi sd gia ca theo phuang phap Laspeyres:

- Chi sd gia theo phuang phap Paashe:

^- J _ T,Pu% ^ ZA,gi, ^ Z^w

'"^^«'^"'z.%„?i,'l''"

[pi 'pi

Trong dd:

- PI,; PO, - Gia ca mat hang i ky bao cao va ky gdc

- q.,; qo, - ^^ong hang hda tieu thy ky bao cao, ky

goc

- Pifli,; Poflo, - Sd tiin chi tfeu (doanh thu ban hang)

ciia hang hda i ky bao cao va ky goc

- i„ - Chi so ca thl vl gia ban mat hang i ( / = - ^ )

Po,

- do,; d,,- Ca cau chi tieu dimg cua timg nhdm

hang hda i ky bao cao, ky gdc

Qua hai cdng thirc tren ta thay, neu chgn cdng

thirc Laspeyres de nghien ciru sy bien dgng cua gia

ca ndi chung, quyen sd dugc chgn d ky gdc. Cdng

thirc vdi quyen sd d ky gdc da triet de loai bd anh

hudng cua nhan td khdng can nghien ciru tdi nhan

td djnh nghien cuu sy bien ddng, mat khac vdi

quyen sd d ky gdc, sd lieu thudng cd sin. Tuy

nhien, cdng thirc nay cd nhugc diem la khdng

phan anh cap nhat dugc nhCfng sy thay ddi ve

khuynh hudng, thdi quen cua ngudi tieu dimg.

Mdt sd mat hang nao dd nhieu nam trudc day dugc

ngudi tieu dung ua chugng va tieu dung vdi so

lugng Idn, nhung ngay nay cd thl khdng cdn quan

trgng vdi hg. Dilu nay Iam cho chi so tfnh theo

Laspeyres khdng cdn phii hgp.

Neu chgn cdng thirc Paashe (cdng thirc vdi

quyln sd la lugng hang hda tieu thu hoac ca ciu

chi tieu d ky bao cao) dl xem xet sy biln ddng cua

gia ca, thi cdng thirc nay da khic phue nhugc dilm

cua phuang phap Laspeyres. Tuy nhien, nlu dung

cdng thirc nay dl nghien ciru sy biln ddng ciia gii

ca, ngoai viec phan anh sy biln ddng ciia gia ca,

trong nhifng chirng myc nhit dinh chi sd nay con

phan anh sy biln dgng ciia iugiig hang hda tieu thy

va anh hudng cua nd tdi mifc gia chung- Dilu dd

cd nghTa la cdng thurc nay khdng triet dl loai trir

anh hudng cua nhan td khdng djnh nghien ciru tdi

sy bien ddng cua nhan to cin nghien curu, M5t

khac, dung cdng thurc nay dl nghien curu sy bien

Tgp chf nghien cdu Tdi chinh ke todn

\