Dear friends,

I have encountered a simple problem. And it may be not related to dynare.

I saw Prof. Pfeifer’s paper(2014) used Fernald’s newest data as TFP.

Is it also measured as TFP volatility?

Also, I am confused how to transform Fernald’s series (dTFP) into TFP.

Is it just the inverse of log difference?

Sorry! Thanks in advance!

We used the following Matlab code to get the levels:

```
[d_TFP]=xlsread('fernald_tfp.xlsx','quarterly','N4:N276');
tfp_obs = cumsum((d_TFP-nanmean(d_TFP))/400); % as Fernald series is annualized in percent
```

where the first period is now 1947Q2.

Hi, professor!

Thanks for your help!!

(Some other literature also uses the method of garch to compute it.)

GARCH is a different concept without volatility shocks and thus not really a structural approach suitable for models.

Hi, professor!

Okay. So much thanks for your advice!

Hi professor,

I used your matlab code to transform Fernald’s series(dTFP) into TFP.

While i get the TFP series include negative values and the sequence increases first and then decreases.

Is there something wrong?Could you please tell me ?

Sorry! Thank you very much!

The code above takes out the trend (the `nanmean`

-part). So it is expected that it fluctuates around 0.