A formula approach below. However, note that since a student is doing the test multiple times it would be possible for them to get their highest (or lowest) score on 2 or more different dates with different EFL values.
If that occurs, my formulas would return the most recent date when the highest/lowest score was achieved & the corresponding EFL on that date (see lowest scores for Mary below).
<b>Test Results</b><br /><br /><table border="1" cellspacing="0" cellpadding="0" style="font-family:Arial,Arial; font-size:8pt; background-color:#ffffff; padding-left:2pt; padding-right:2pt; "> <colgroup><col style="font-weight:bold; width:30px; " /><col style="width:68px;" /><col style="width:94px;" /><col style="width:98px;" /><col style="width:102px;" /><col style="width:89px;" /><col style="width:43px;" /><col style="width:68px;" /><col style="width:94px;" /><col style="width:98px;" /><col style="width:50px;" /><col style="width:88px;" /><col style="width:78px;" /><col style="width:49px;" /><col style="width:87px;" /><col style="width:77px;" /><col style="width:89px;" /></colgroup><tr style="background-color:#cacaca; text-align:center; font-weight:bold; font-size:8pt; "><td > </td><td >A</td><td >B</td><td >C</td><td >D</td><td >E</td><td >F</td><td >G</td><td >H</td><td >I</td><td >J</td><td >K</td><td >L</td><td >M</td><td >N</td><td >O</td><td >P</td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >1</td><td style="font-size:10pt; text-align:right; ">ID</td><td style="font-size:10pt; ">LAST NAME</td><td style="font-size:10pt; ">FIRST NAME</td><td style="font-size:10pt; text-align:right; ">TEST SCORE</td><td style="font-size:10pt; text-align:right; ">TEST DATE</td><td style="font-size:10pt; text-align:right; ">EFL</td><td style="font-size:10pt; text-align:right; ">ID</td><td style="font-size:10pt; ">LAST NAME</td><td style="font-size:10pt; ">FIRST NAME</td><td style="font-size:10pt; text-align:right; ">HIGH</td><td style="font-size:10pt; text-align:right; ">HIGH DATE</td><td style="font-size:10pt; text-align:right; ">HIGH EFL</td><td style="font-size:10pt; text-align:right; ">LOW</td><td style="font-size:10pt; text-align:right; ">LOW DATE</td><td style="font-size:10pt; text-align:right; ">LOW EFL</td><td style="font-size:10pt; text-align:right; ">LAST DATE</td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >2</td><td style="font-size:10pt; text-align:right; ">1771234</td><td style="font-size:10pt; ">SMITH</td><td style="font-size:10pt; ">ALLEN</td><td style="font-size:10pt; text-align:right; ">450</td><td style="font-size:10pt; text-align:right; ">4/08/2019</td><td style="font-size:10pt; text-align:right; ">1</td><td style="font-size:10pt; text-align:right; ">1771234</td><td style="font-size:10pt; ">SMITH</td><td style="font-size:10pt; ">ALLEN</td><td style="font-size:10pt; text-align:right; ">600</td><td style="font-size:10pt; text-align:right; ">2/09/2019</td><td style="font-size:10pt; text-align:right; ">5</td><td style="font-size:10pt; text-align:right; ">450</td><td style="font-size:10pt; text-align:right; ">4/08/2019</td><td style="font-size:10pt; text-align:right; ">1</td><td style="font-size:10pt; text-align:right; ">8/10/2019</td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >3</td><td style="font-size:10pt; text-align:right; ">1771235</td><td style="font-size:10pt; ">ABIL</td><td style="font-size:10pt; ">NOE</td><td style="font-size:10pt; text-align:right; ">562</td><td style="font-size:10pt; text-align:right; ">4/09/2019</td><td style="font-size:10pt; text-align:right; ">2</td><td style="font-size:10pt; text-align:right; ">1771235</td><td style="font-size:10pt; ">ABIL</td><td style="font-size:10pt; ">NOE</td><td style="font-size:10pt; text-align:right; ">562</td><td style="font-size:10pt; text-align:right; ">4/09/2019</td><td style="font-size:10pt; text-align:right; ">2</td><td style="font-size:10pt; text-align:right; ">562</td><td style="font-size:10pt; text-align:right; ">4/09/2019</td><td style="font-size:10pt; text-align:right; ">2</td><td style="font-size:10pt; text-align:right; ">4/09/2019</td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >4</td><td style="font-size:10pt; text-align:right; ">1771236</td><td style="font-size:10pt; ">VILLA</td><td style="font-size:10pt; ">MARY</td><td style="font-size:10pt; text-align:right; ">489</td><td style="font-size:10pt; text-align:right; ">1/10/2019</td><td style="font-size:10pt; text-align:right; ">3</td><td style="font-size:10pt; text-align:right; ">1771236</td><td style="font-size:10pt; ">VILLA</td><td style="font-size:10pt; ">MARY</td><td style="font-size:10pt; text-align:right; ">596</td><td style="font-size:10pt; text-align:right; ">30/08/2019</td><td style="font-size:10pt; text-align:right; ">7</td><td style="font-size:10pt; text-align:right; ">489</td><td style="font-size:10pt; text-align:right; ">1/10/2019</td><td style="font-size:10pt; text-align:right; ">3</td><td style="font-size:10pt; text-align:right; ">1/10/2019</td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >5</td><td style="font-size:10pt; text-align:right; ">1771234</td><td style="font-size:10pt; ">SMITH</td><td style="font-size:10pt; ">ALLEN</td><td style="font-size:10pt; text-align:right; ">545</td><td style="font-size:10pt; text-align:right; ">8/10/2019</td><td style="font-size:10pt; text-align:right; ">4</td><td style="font-size:10pt; text-align:right; ">1771239</td><td style="font-size:10pt; ">ESQUIVEL</td><td style="font-size:10pt; ">MARIO</td><td style="font-size:10pt; text-align:right; ">520</td><td style="font-size:10pt; text-align:right; ">25/09/2019</td><td style="font-size:10pt; text-align:right; ">6</td><td style="font-size:10pt; text-align:right; ">520</td><td style="font-size:10pt; text-align:right; ">25/09/2019</td><td style="font-size:10pt; text-align:right; ">6</td><td style="font-size:10pt; text-align:right; ">25/09/2019</td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >6</td><td style="font-size:10pt; text-align:right; ">1771234</td><td style="font-size:10pt; ">SMITH</td><td style="font-size:10pt; ">ALLEN</td><td style="font-size:10pt; text-align:right; ">600</td><td style="font-size:10pt; text-align:right; ">2/09/2019</td><td style="font-size:10pt; text-align:right; ">5</td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >7</td><td style="font-size:10pt; text-align:right; ">1771239</td><td style="font-size:10pt; ">ESQUIVEL</td><td style="font-size:10pt; ">MARIO</td><td style="font-size:10pt; text-align:right; ">520</td><td style="font-size:10pt; text-align:right; ">25/09/2019</td><td style="font-size:10pt; text-align:right; ">6</td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >8</td><td style="font-size:10pt; text-align:right; ">1771236</td><td style="font-size:10pt; ">VILLA</td><td style="font-size:10pt; ">MARY</td><td style="font-size:10pt; text-align:right; ">596</td><td style="font-size:10pt; text-align:right; ">30/08/2019</td><td style="font-size:10pt; text-align:right; ">7</td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td></tr><tr style="height:21px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >9</td><td style="font-size:10pt; text-align:right; ">1771236</td><td style="font-size:10pt; ">VILLA</td><td style="font-size:10pt; ">MARY</td><td style="font-size:10pt; text-align:right; ">489</td><td style="font-size:10pt; text-align:right; ">30/08/2019</td><td style="font-size:10pt; text-align:right; ">8</td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td><td style="font-size:10pt; "> </td></tr></table><br /><table style="font-family:Arial; font-size:10pt; border-style: groove ;border-color:#00ff00;background-color:#fffcf9; color:#000000; "><tr><td ><b>Spreadsheet Formulas</b></td></tr><tr><td ><table border = "1" cellspacing="0" cellpadding="2" style="font-family:Arial; font-size:9pt;"><tr style="background-color:#cacaca; font-size:10pt;"><td >Cell</td><td >Formula</td></tr><tr><td >G2</td><td >=IFERROR(INDEX<span style=' color:008000; '>($A$2:$A$100,MATCH<span style=' color:#0000ff; '>(0,INDEX<span style=' color:#ff0000; '>(COUNTIF<span style=' color:#804000; '>($G$1:G1,$A$2:$A$100)</span>+<span style=' color:#804000; '>(A$2:A$100="")</span>,0)</span>,0)</span>)</span>,"")</td></tr><tr><td >H2</td><td >=IF($G2="","",INDEX<span style=' color:008000; '>(B$2:B$100,MATCH<span style=' color:#0000ff; '>($G2,$A$2:$A$100,0)</span>)</span>)</td></tr><tr><td >I2</td><td >=IF($G2="","",INDEX<span style=' color:008000; '>(C$2:C$100,MATCH<span style=' color:#0000ff; '>($G2,$A$2:$A$100,0)</span>)</span>)</td></tr><tr><td >J2</td><td >=IF($G2="","",AGGREGATE<span style=' color:008000; '>(14,6,D$2:D$100/<span style=' color:#0000ff; '>($A$2:$A$100=$G2)</span>,1)</span>)</td></tr><tr><td >K2</td><td >=IF(G2="","",AGGREGATE<span style=' color:008000; '>(14,6,E$2:E$100/<span style=' color:#0000ff; '>(<span style=' color:#ff0000; '>(A$2:A$100=G2)</span>*<span style=' color:#ff0000; '>(D$2:D$100=J2)</span>)</span>,1)</span>)</td></tr><tr><td >L2</td><td >=IF(G2="","",INDEX<span style=' color:008000; '>(F:F,AGGREGATE<span style=' color:#0000ff; '>(15,6,ROW<span style=' color:#ff0000; '>(F$2:F$100)</span>/<span style=' color:#ff0000; '>(<span style=' color:#804000; '>(A$2:A$100=G2)</span>*<span style=' color:#804000; '>(D$2:D$100=J2)</span>*<span style=' color:#804000; '>(E$2:E$100=K2)</span>)</span>,1)</span>)</span>)</td></tr><tr><td >M2</td><td >=IF($G2="","",AGGREGATE<span style=' color:008000; '>(15,6,D$2:D$100/<span style=' color:#0000ff; '>($A$2:$A$100=$G2)</span>,1)</span>)</td></tr><tr><td >N2</td><td >=IF(G2="","",AGGREGATE<span style=' color:008000; '>(14,6,E$2:E$100/<span style=' color:#0000ff; '>(<span style=' color:#ff0000; '>(A$2:A$100=G2)</span>*<span style=' color:#ff0000; '>(D$2:D$100=M2)</span>)</span>,1)</span>)</td></tr><tr><td >O2</td><td >=IF(G2="","",INDEX<span style=' color:008000; '>(F:F,AGGREGATE<span style=' color:#0000ff; '>(15,6,ROW<span style=' color:#ff0000; '>(F$2:F$100)</span>/<span style=' color:#ff0000; '>(<span style=' color:#804000; '>(A$2:A$100=G2)</span>*<span style=' color:#804000; '>(D$2:D$100=M2)</span>*<span style=' color:#804000; '>(E$2:E$100=N2)</span>)</span>,1)</span>)</span>)</td></tr><tr><td >P2</td><td >=IF($G2="","",AGGREGATE<span style=' color:008000; '>(14,6,E$2:E$100/<span style=' color:#0000ff; '>($A$2:$A$100=$G2)</span>,1)</span>)</td></tr></table></td></tr></table>