Talk:Input-output model

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This article is based on class notes developed by William Lewis Garrison, and edited by User:DavidLevinson and used with permission.

aaa I want to insert the equation $$ X = \left[ {\matrix

  {x_1 }  \\ 
  {x_2 }  \\ 
  {x_3 }  \\ 
  {x_4 }  \\ 

\endmatrix } \right]\quad C = \left[ {\matrix
  {c_1 }  \\ 
  {c_2 }  \\ 
  {c_3 }  \\ 
  {c_4 }  \\ 

\endmatrix } \right]\quad I = \left[ {\matrix
  1 & 0 & 0 & 0  \\ 
  0 & 1 & 0 & 0  \\ 
  0 & 0 & 1 & 0  \\ 
  0 & 0 & 0 & 1  \\ 

\endmatrix } \right]\;A = \left[ {\matrix
  {a_{11} } & {} & {} & {a_{14} }  \\ 
  {} & {} & {} & {}  \\ 
  {} & {} & {} & {}  \\ 
  {a_{41} } & {} & {} & {a_{44} }  \\ 

\endmatrix } \right]

$$

but the software can't parse. dml 13:38, 9 Oct 2004 (UTC)

Yes they should be merged, but I suspect that in time both shall be supplanted with deeper more thorough entries.

MikelahrMike Lahr

Support merge JQ 23:06, 6 May 2006 (UTC)

[edit] title should be changed

title should be:

Input-output model (economics)

[edit] Grave error in explanation of concept?

I was reading the following paragraph to try to get a grasp of the concept: Each row of the input-output matrix reports the monetary value of an industry's inputs and each column represents the value of an industry's outputs. Suppose there are three industries. Row 1 reports the value of inputs to Industry 1 from Industries 1, 2, and 3. Rows 2 and 3 do the same for those industries. Column 1 reports the value of outputs from Industry 1 to Industries 1, 2, and 3. Columns 2 and 3 do the same for the other industries.

Comparing that to my other source (a 10 page copy from a book with a chapter called "Foundations of Input-Output analysis", i don't know what the book is called but it looks like it's quite credible) the whole paragraph above seems to be opposite of what is correct.

Here is one example from the book:
X      1         2
1    0.15    0.25
2    0.20    0.05

And the text says: "To produce one dollar worth of goods from sector 2 one needs as interindustry ingredients 25cents worth of good 1 and 5cents worth of good 2."
I would translate that to: Column 2 reports the value of inputs to Industry 2 from Industries 1 and 2.
Opposite of what the paragraph in the wikipedia article says.

Can someone correct me or verify this? I'm new to this whole concept.

Mariux 17:50, 14 May 2007 (UTC)Marius

I agree regarding "Grave error"

Funny that we should stumble upon this at about the same time. I agree that the text in the first section is reversed. The proposed correction is: Row 1 reports the output from Industry 1 used as inputs in Industries 1, 2, and 3; that is, Row 1 describes the use of output from Industry 1 as an input in other industries. Column 1 reports the value of inputs to Industry 1 that were produced in Industries 1, 2, and 3; that is, Column 1 describes the use as inputs to Industry 1 of outputs from other industries.

I don't feel confident enough to make the change myself, but I hope that someone else will. (It's obviously pretty easy to get tripped up here.)

The table in the section Key Ideas is correct. Note that Labor, an input, has its own row and Final Demand an output, has its own column.

Michaelaoash 09:08, 23 May 2007 (UTC)

Is there a way we atleast could mark the passage with 'disputed' or something?
Mariux 17:56, 26 May 2007 (UTC)

not quite a "grave error", it is just definitional, what is a row and what is a column, what I think you are questioning, is arbitrary, and different expositions use different customs. Just as putting price on the Y-axis and quantity and the X-axis in economics is customary, but sometimes reversed. However the article should be internally consistent, so I reversed row and column in introduction as suggested. dml 18:03, 6 July 2007 (UTC)

[edit] Style issues

1. The crucial concept of the Leontief coefficient a_ij is not explained. Is it the amount of input i needed for a unit of output j, or the other way round?

2. It is pretentious to refer to the Nobel Prize for Economics by its full legal title, which is given in the relevant Wikipedia page.

--JamesWim 17:18, 6 October 2007 (UTC)