<p>I had a look at the data, and it is like @denesp says in his comment: e.g. a $2.60\%=0.0261$ population growth rate is written as $2.60$, a $24\%=0.24$ investment-to-output ratio is written like $24.0$, etc. 
So they must be divided by $100$.</p>

CC BY-SA 3.0
2016-03-30T12:46:36.730Z
Thanks Alecos. You're right. I don't know how I missed that ... =D
An old man in the sea.
CC BY-SA 3.0
2016-03-29T23:46:41.710Z
2016-03-29T23:46:41.710Z
Alecos Papadopoulos
<p>I'm trying to replicate the regression of the <a href="http://dx.doi.org/10.2307/2118477" rel="nofollow">MRW 1992</a> paper.
(<a href="https://www.nuffield.ox.ac.uk/teaching/economics/bond/mrw.dta" rel="nofollow">Here's</a> the data, if you're interested)</p>

<p>In the same page where the data set is available, there's this <a href="https://www.nuffield.ox.ac.uk/teaching/economics/bond/OLS%20Regression%20Using%20Stata.pdf" rel="nofollow">handout</a> explaining how to replicate the results. In page 2 of this handout, we can see two simple stata commands: </p>

<pre><code>li_y=ln(i_y/100) 
 g lpop=ln(0.05+popgrowth/100)
</code></pre>

<p>My question is why the variables <code>i_y</code> (this is Investment over GDP), and <code>popgrowth</code>(this is an averaged population growth rate between 1960-1985) are divided by 100?</p>

<p>Nowhere in the MRW 1992 paper, do I read something telling me that it's necessary to divide it by 100, or do I?</p>

<p>Any help would be appreciated</p>

CC BY-SA 3.0
2016-03-29T23:05:26.933Z
Perhaps in the data they are given as percentage points?
Giskard
CC BY-SA 3.0
2016-03-31T04:05:16.123Z
It's just a scaling factor get everything as a decimal.
D J Sims
CC BY-SA 3.0
2016-05-08T16:48:15.323Z
Are you aware of the [2013 replication](http://replication.uni-goettingen.de/wiki/index.php/Is_newer_better%3F_Penn_World_Table_Revisions_and_their_impact_on_growth_estimates_(JME_2013))?
Jan Höffler
<macroeconomics>
A doubt on the Regression of Mankiw, Romer, Weil 1992 paper
An old man in the sea.
# A doubt on the Regression of Mankiw, Romer, Weil 1992 paper

(Asked by: username_0 on 2016-03-29)

I'm trying to replicate the regression of the [MRW 1992](http://dx.doi.org/10.2307/2118477) paper.
([Here's](https://www.nuffield.ox.ac.uk/teaching/economics/bond/mrw.dta) the data, if you're interested)

In the same page where the data set is available, there's this [handout](https://www.nuffield.ox.ac.uk/teaching/economics/bond/OLS%20Regression%20Using%20Stata.pdf) explaining how to replicate the results. In page 2 of this handout, we can see two simple stata commands:

```
li_y=ln(i_y/100) 
 g lpop=ln(0.05+popgrowth/100)

```

My question is why the variables `i_y` (this is Investment over GDP), and `popgrowth`(this is an averaged population growth rate between 1960-1985) are divided by 100?

Nowhere in the MRW 1992 paper, do I read something telling me that it's necessary to divide it by 100, or do I?

Any help would be appreciated

**Tags:** macroeconomics

> **Comments:**
> **username_1**: Perhaps in the data they are given as percentage points?  
> **username_2**: It's just a scaling factor get everything as a decimal.  
> **username_3**: Are you aware of the [2013 replication](http://replication.uni-goettingen.de/wiki/index.php/Is_newer_better%3F_Penn_World_Table_Revisions_and_their_impact_on_growth_estimates_(JME_2013))?  

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## 1 answers

### Answer by username_4 on 2016-03-29. Score: 2 | Accepted answer

I had a look at the data, and it is like @denesp says in his comment: e.g. a $2.60\%=0.0261$ population growth rate is written as $2.60$, a $24\%=0.24$ investment-to-output ratio is written like $24.0$, etc.
So they must be divided by $100$.

> **Comments:**
> **username_0**: Thanks username_4. You're right. I don't know how I missed that ... =D  

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